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The Sealed Attic System with DuPontTM Tyvek® AtticWrapTM INSTALLATION MANUAL

DuPontTM Tyvek® AtticWrapTM RevealedThe sealed attic vented roof system uses DuPontTM Tyvek® AtticWrapTM airtight membrane to establish an air barrier beneath the roof sheathing.

The blue arrows indicate the path air follows from eave to ridge between the layer of Tyvek® AtticWrapTM and the roof sheathing.

Functioning as an air barrier, Tyvek® AtticWrapTM helps prevent interior conditioned air from leaking into the attic by blocking air loss from the attic.

Tyvek® AtticWrapTM is vapor permeable so water vapor that reaches the attic from inside the house can diffuse through it and into the vent channels.

CONTENTS

Introduction 2

Science Behind Sealed Attic Vented Roof System 3

Benefits 5

Installation Overview 6

Safety 7

Installation Methods

Furring Method 8

Rafter Cap Method 12

Drape Method 16

Common Details 20

Glossary 23

Frequently Asked Questions 24

Product Specifications 26

DuPontTM Tyvek® AtticWrapTM Installation Manual

At DuPont, we use science to develop innovative products

that work together to create healthier, safer, more attractive

and more environmentally-sustainable buildings and homes.

With more than 75 research and development facilities

around the world, we’re focused on creating revolutionary

new products to help today’s builders, architects and

contractors create structures that are stronger, safer,

more comfortable and longer-lasting. From materials that

can help a room withstand storm and blast impacts, to

improved glass performance, durable wood alternatives and

breathable barriers to seal the building envelope against

moisture, mold and air penetration, DuPont has a blueprint

for the future of construction.

DuPontTM Tyvek® is a true miracle of science. Made from

very fine, high-density polyethylene fibers, DuPontTM Tyvek®

offers all the best characteristics of paper, film and fabric in

one material. It has provided new dimensions of protection,

security and safety for a wide variety of industries.

DuPont continues to invent new products and techniques.

Now, the DuPontTM Tyvek® weatherization systems products

include Tyvek® HomeWrap®, Tyvek® CommercialWrap®,

Tyvek® StuccoWrap®, Tyvek® DrainWrapTM, DuPontTM

FlexWrapTM, DuPontTM StraightFlashTM, DuPontTM Tyvek® Tape,

DuPontTM Tyvek® Fasteners, and our newest miracles of

science, Tyvek® AtticWrapTM and Tyvek® ThermaWrapTM.

Our specialist network is a national group of over 160

highly-trained field representatives available to assist

customers with their installations. From the latest updates

on building codes to on-site consulting and training, your

local DuPontTM Tyvek® Specialist will help make sure each

installation is done right.

BUILDING TODAY FOR A BETTER TOMORROW

Tyvek® AtticWrap™ allows water vapor through while it repels bulk water. Above, the release liner is pulled back to reveal the integrated adhesive strip; at left, Tyvek® AtticWrap™

is positioned on a roof prior to fastening.

3

This installation guide contains information on

the function, use and installation of the DuPontTM

Tyvek® AtticWrapTM membrane. Tyvek®

AtticWrapTM, along with other DuPontTM Tyvek®

products, can help improve the durability and

energy effi ciency of buildings by helping to control

heat, moisture and air movement through the

building envelope.

Modern North American attic spaces are vented

with exterior air. The exterior ventilation air is

intended to dilute moisture vapor entering the

attic through air leaks from inside the building.

This helps reduce the chance of the moisture

condensing on the roof sheathing and framing,

which can lead to mold and rot.

However, introducing exterior ventilation air into

an attic can have some unintended negative

side effects. Vent air can shortcut and circulate

through insulation such as fi berglass and reduce

its effectiveness through a process called “wind

wash.” Vent air can also accelerate the leakage

of conditioned air from inside the building. And

in humid climates, external vent air can introduce

moisture into the roof structure.

Ventilation space between the membrane and the roof sheathing provides continuous eave-to-ridge air ventilation

Tyvek® AtticWrap™ establishes an air barrier over the roof framing and eaves, and ties into Tyvek® HomeWrap® on the walls to create a whole-house weather seal

Tyvek® AtticWrap™ cuts off the stack effect, which helps prevent interior-conditioned air from escaping

Outside air travelsthrough ceiling insulation,reducing the effective R-value

Roof ventilation depends on hot air rising, but the draw pulls conditioned air through holes in the ceiling and partition walls

Air escaping from inside the building introduces moisture into the roof structure, where it can condense on attic surfaces and lead to mold and rot

Tyvek® AtticWrap™ helps keep moisture introduced by ventilating air away from the roof structure and ceiling insulation

SEALED ATTIC VENTED ROOF SYSTEM

3

The sealed attic vented roof system establishes

an air barrier beneath the roof sheathing using

DuPontTM Tyvek® AtticWrapTM airtight membrane.

Tyvek® AtticWrapTM is applied over the roof

rafters to create vent channels beneath the

roof sheathing. This space provides continuous

eave-to-ridge air ventilation to cool the roofi ng

material and to help carry away moisture vapor.

Functioning as an air barrier, Tyvek® AtticWrapTM

helps prevent interior conditioned air from leaking

into the attic by blocking air loss from the attic.

Tyvek® AtticWrapTM is moisture permeable so

moisture vapor that reaches the attic from inside

the house can diffuse through it and into the

vent channels.

Tyvek® AtticWrapTM is also water resistant and

serves as a secondary drainage plane for the

roof. In the event water leaks through the roofi ng

material or fl ashings due to ice damming, damage,

wear or improper installation, or from water driven

up through the eave vents during a storm, Tyvek®

AtticWrapTM channels water through the vent space

down to the eaves where it can drain. Tyvek®

AtticWrapTM helps provide back-up water intrusion

protection in case of roof leaks, keeping the attic

space and the inside of the home safe and dry.

Tyvek® AtticWrap™ provides a secondary drainage plane for the roof. Moisture vapor that migrates into the attic diffuses through Tyvek® AtticWrap™ and into the vent channels where it is carried away by exterior ventilation air. The airtight attic creates a dry, semi-conditioned space.

Moisture diffuses into ventilation space

Conditioned Air

Metalized surface

Wind

Tyvek® AtticWrap™

serves as a secondary drainage plane

Sealed soffi ts and rafter bays

Air channel

Conditioned Air

Semi-conditioned air is kept within attic space

The metalized surface on Tyvek® AtticWrap™ helps reduce heat build up in the attic. Air channels beneath the sheathing cools the roofi ng materials. The sealed rafter bays drain roof leaks and wrapped eaves resist water intrusion in high-wind areas.

4 5

SEALED ATTIC VENTED ROOF SYSTEM continued

THE SEALED ATTIC SYSTEM WITH DUPONTTM TYVEK® ATTICWRAPTM PROVIDES A WEALTH OF BENEFITS

Helps cut overall cooling and heating costs

Radiant heat gain in the attic during summer

adds to cooling costs. The underside of DuPontTM

Tyvek® AtticWrapTM is layered with a radiantly

reflective metalized material and the low

emissivity of the surface reduces heat gain and

keeps the attic cooler. During the heating season,

the radiant layer reflects heat back into the attic

and reduces heat loss.

Regulates attic temperature

An airtight attic seals in warm air during the

winter. In the summer an airtight attic stays

cooler because the cooling ventilation air

circulates directly beneath the roof sheathing,

while the Tyvek® AtticWrapTM reflects the heat

away from the attic. Tyvek® AtticWrapTM also

helps prevent insect pests, dust and pollen from

entering the attic while still permitting moisture

vapor to pass through and exit. The result is a

semi-conditioned attic space suitable for storage

without concern of contamination.

Reduces energy use

Because Tyvek® AtticWrapTM creates an

airtight attic, conditioned interior air is less likely

to leak through the ceiling from the living space

and into the attic. Air conditioning, heating

equipment and ductwork installed in a sealed

attic lose less energy as well.

Improves insulation performance

When conventional ventilation air moves

through attic shortcuts and around attic insulation,

it reduces the insulation’s effectiveness and robs

energy from the building. But a sealed attic helps

stop adverse effects by eliminating air movement,

resulting in improved insulation performance.

Tyvek® AtticWrapTM protects the installed R-value

of attic insulation.

Enhances roof ventilation air flow

Tyvek® AtticWrapTM keeps insulation from

blocking off the ventilation air channel, which

allows air to flow freely between the roof

sheathing and membrane. The ventilation air

dissipates moisture vapor that passes through

Tyvek® AtticWrapTM as it cools the roof.

Channels moisture vapor Moisture vapor passes safely through Tyvek®

AtticWrapTM, so vapor that enters the attic from

inside the living space can diffuse through the

membrane and into the vent channel where it

mixes with ventilation air and is carried away.

Acts as a secondary weather barrier Roofs can leak due to ice damming, storm

damage, improper or damaged flashings, or

severe weather. Tyvek® AtticWrapTM collects

leaking water and channels it to the eaves where

it can drain outside the building. In coastal, high

wind and hurricane prone areas where rain can

penetrate the attic through the soffits, Tyvek®

AtticWrapTM blocks water infiltration into the

building and allows it to drain safely out

of the house.

Reduces chance of ice damming Ice dams form when snow on the roof melts

and refreezes near the edge of the eaves. This

can lead to roof leaks. Tyvek® AtticWrapTM helps

reduce ice dams by keeping the roof surface

cold in two ways. First, it creates an airtight attic

that prevents warm air from reaching the roof

sheathing where it would accelerate melting.

Second, the air channel created by Tyvek®

AtticWrapTM directs ventilation air directly

beneath the roof, helping to keep it cold.

Helps protect asphalt shingles

The air channel created by Tyvek® AtticWrapTM

directs ventilation air directly beneath the roof

sheathing. The ventilation air moves faster in the

air channel than it does in a conventionally vented

roof. Therefore, the moving air cools the roof

sheathing and shingles, helping to protect the

whole roof system.

Moisture diffuses into ventilation space

4 5

6 7

OVERVIEW OF THREE PRIMARY DUPONTTM TYVEK® ATTICWRAPTM INSTALLATION METHODS

There are three basic installation methods

for applying DuPontTM Tyvek® AtticWrapTM:

the Furring, the Rafter Cap and the Drape

methods. With each method, DuPontTM

Tyvek® AtticWrapTM is applied over the roof

rafters or trusses before the roof sheathing

is installed. Each method creates vent

channels beneath the roof sheathing

between the rafters or trusses. Air flowing

through the vent channels cools the roof

surface and carries away moisture vapor

that diffuses through the membrane. The

vent channels also act as “gutters” to

collect water that leaks through the roofing

or flashings and to drain it out through

the soffits. Each Tyvek® AtticWrapTM

installation method is described separately:

Furring method, pp. 8-11; Rafter Cap

method, pp. 12-15; and Drape method pp.

16-20. After reviewing all three methods,

choose one that best suits your project.

In some cases, more than one installation

method will be appropriate and can be

used on the same roof.

Eave Details for Venting

To create a sealed airtight attic, DuPontTM

Tyvek® AtticWrapTM must wrap around

the eaves of the roof and be sealed to

the housewrap such as DuPontTM Tyvek®

HomeWrapTM. There are numerous

strategies you can use to seal Tyvek®

AtticWrapTM at the eaves and to the

housewrap. With some strategies the

Tyvek® AtticWrapTM membrane wraps

around the eaves, and with others, the

membrane is slit and folded between rafter

tails or terminated at the exterior wall line.

Each detail is constructed to maintain a

free flow of ventilation air and to drain

water as well. The choice of which detail

to use depends on the type of soffit, facia

or eave vent used on the building.

The Tyvek® AtticWrapTM eave installation

details are grouped together on the pages

following each installation method. Many

eave details have alternates showing rafter

or truss tails with and without subfacias.

Plan the air intake as well as water

drainage when choosing an installation

detail. It’s important to permit a free-flow

of ventilation air entering along the eave

edge or soffit and into the vent channels.

Some less common eave detail designs are

included near the end of the guide.

FURRING METHOD

RAFTER CAP METHOD

DRAPE METHOD

While we have tried to include DuPontTM

Tyvek® AtticWrapTM sealing and eave venting

details for most common roof configurations

and obstructions, not every possibility is

addressed. When constructing Tyvek®

AtticWrapTM details not described here, it

is important to provide a clear ventilation

air channel, to seal the membrane at

penetrations and edges keeping it watertight

and airtight, and to maintain the slope of the

membrane to prevent water from ponding.

Tyvek® AtticWrapTM product informationTyvek® AtticWrapTM comes in rolls 4 ft.

11 in. wide by 164 feet long with an

integrated adhesive strip along the top edge.

Successive sheets are overlapped 6 inches.

One roll of Tyvek® AtticWrapTM covers about

7 squares (700 sq. ft.) of roof area when

using the Furring method of installation, and

6 squares (600 sq. ft.) using the Rafter Cap

or Drape methods.

General installation notesTyvek® AtticWrapTM is usually installed

horizontally across rafters or trusses but

can be installed vertically as well. Install roof

sheathing after each horizontal course of

Tyvek® AtticWrapTM is applied. The sheathing

acts as a work and walk surface to apply

successive Tyvek® AtticWrapTM courses from.

The optimal installation crew size is 2 to 3

workers.

Full rolls of Tyvek® AtticWrapTM are bulky to

work with. Precut Tyvek® AtticWrapTM on the

ground to make handling easier on the roof.

Cut lengths of Tyvek® AtticWrapTM 12 in.

longer than the roof length when using

the Furring installation method. Add an

additional 3 in. per rafter or truss bay when

using the Rafter Cap or Drape methods.

For the purposes of this installation guide,

we will use the terms “rafter” to refer to

both rafters and fabricated roof trusses.

In some instances we will refer to “truss”

where trussed roof installation procedures

differ from those roofs framed with rafters.

Whenever you’re working on the roof, you are at high-risk. Falls can

result in serious injury, so it’s essential that you adhere to high-

safety standards while you are installing Tyvek® AtticWrapTM. For

your own safety and the safety of other workers, you should use fall

protection suitable for the jobsite conditions.

To find out more about a fall protection plan, refer to the OSHA

safety regulations 29 CFR1926. Other good sources for fall protection

guidance are the NAHB-OSHA Jobsite Safety Handbook and the

NAHB-OSHA Scaffold Safety Handbook.

Please remember that Tyvek® AtticWrapTM is a durable membrane,

but it is not intended to be walked or leaned on. It is not designed

to support your weight between rafters.

WHEN WORKING ON A ROOF, PLEASE FOLLOW THESE GUIDELINES:

•Always ask “What if” in every situation that is potentially unsafe.

•Do not walk on Tyvek® AtticWrapTM or leave it rolled out on floors so

others may walk on it. This represents a slipping hazard.

•Do not put your weight on the membrane once it’s installed. It is

not designed to support your weight.

•Take the time to evaluate each job for the safest and most expedient

way to access the elevated work areas.

•Your fall protection plan will help you identify and avoid hazards on

the site. Your regional OSHA office or local builder’s association can

help you draft your plan. The person developing your plan needs to

know that:

•Lifelines and lanyards must have no less than

5000 lbs. breaking strength.

•The anchorage for those lifelines must be able to

support 5000 lbs.

•The whole system of harness, lanyard, lifeline and anchor

must be strong enough to withstand twice the impact energy

of a worker free-falling a distance of 6 ft., or the free-fall

distance permitted by the system, whichever is less.

•Use a complete rope and harness system made by a reputable

manufacturer and follow the instructions carefully.

•There are more than two dozen types of scaffolds mentioned in

OSHA’s safety rules for construction. Read the instructions carefully.

•If you are using ladders, be sure to secure them at the top and

bottom. Ladders need to extend 3 ft. above the landing to provide a

safe handhold when getting on or off.

•Remember, there is no substitute for your own alertness and

common sense.

ROOF SAFETY

6 7

Air fl ow


Furring strip

The Furring method is the simplest installation method

for installing DuPontTM Tyvek® AtticWrapTM. Air vent

channels are created between the roof sheathing and the

Tyvek® AtticWrapTM membrane by applying furring strips

(strips of wood 1 in. or thicker by 11/2 in. or wider) on top

of each rafter over the taut stretched membrane. Vent

space continuity is easy to achieve at the eave edges,

hips, valleys and ridges using this method.

Installers should account for the extra thickness that the

furring adds to the roof when planning facia boards, rake

boards and other roof trim.

Contractors building in high wind and seismic zones

should check with an engineer or local building

department before using the Furring method. The furring

strips may diminish the rigidity of the roof sheathing

diaphragm. The Rafter Cap or Drape installation methods

may be better choices for these locales.

The Furring method is compatible with any insulation type

or installation method including direct contact.

Preparation: Select the DuPontTM Tyvek® AtticWrapTM

eave detail you wish to use and install the required

framing, including subfacias, wall nailers, soffi t blocking

and rafter blocking. Complete all framing work before

installing Tyvek® AtticWrapTM.

Apply the eave course of Tyvek® AtticWrapTM: Snap a chalk line parallel to the eave edge

approximately 12 in. to 16 in. up from the rafter tails.

Roll out a section of Tyvek® AtticWrapTM with the

integrated

adhesive strip at

the top, aligning

the edge of

the membrane

with the chalk

line. Pull the

membrane taut

and staple it to

the tops of the

rafters across

the entire length

of the roof.

Roll out the next course of Tyvek® AtticWrapTM: Align the bottom edge of the roll with the dotted

line on the top edge of the course below. Staple the

membrane taut

to the tops of

rafters, but be

sure to leave

the bottom

6 in. loose for

sealing. Lift the

bottom edge of

overlying course

and peel the

release liner

from the

integrated

adhesive strip

on the course

beneath.

Press the

layers of Tyvek®

AtticWrapTM

together along

the integrated

adhesive strip to

create an airtight

seal.

Align Tyvek® AtticWrapTM to chalk line and fasten to the tops of the rafters

DUPONTTM TYVEK® ATTICWRAPTM INSTALLATION USING FURRING METHOD

STEP ONE

Remove release liner, press sheets together

Align bottom edge with dotted overlap line

STEP TWO

8 9

WRAP TIP Sometimes the integrated adhesive strip doesn’t bond completely in cold weather. After installation is complete, check joints from inside the attic and press loose areas to ensure a tight seal.

Install furring strips over Tyvek® AtticWrapTM: Next, apply a furring strip on top of each rafter

starting at the end of the rafter tail and extending

up to the dotted “overlap” line along the top of

the Tyvek® AtticWrapTM. Furring strips should be a

minimum of 1 in. thick by a minimum of 11/2 in. wide.

Fasten each

furring strip

with 10d or

longer common

nails spaced

approximately

12 in. apart or

according to the

local building

code nailing

schedule.

Install roof sheathing over furring strips: Snap a chalk line across the furring strips as a guide

line for the top

edge of the roof

sheathing.

Install roof

sheathing

following the

local building

code nailing

schedule.

Install successive courses of Tyvek® AtticWrapTM, furring strips and roof sheathing: Install the next course of Tyvek® AtticWrapTM across

the rafters, again aligning it with the dotted line on

the course

below. Seal

the lower edge

to the top of

the course

below using

the integrated

adhesive strip.

Install a furring

strip on each rafter up to the integrated adhesive

strip of the overlying course of Tyvek® AtticWrapTM.

Install roof sheathing over furring strips. Follow the

same sequence until you reach the ridge.

Wrap Tyvek® AtticWrapTM over the ridge: Wrap the top course of Tyvek® AtticWrapTM over the

ridge and onto the other side. Seal the

overlapping

edge with

DuPontTM Tyvek®

Tape. If the

edge of the

membrane

overlaps less

than 10 in. over

the ridge, apply

an additional

sheet of Tyvek®

AtticWrapTM at

least 20 in. wide

over the ridge

to protect this

vulnerable area.

Cut furring strips to top of ridge and sheath: Cut and install furring strips so that they end within

2 in. of the center of ridge board. Rip sheathing to

leave an air slot

at least 11/2 in.

wide at the ridge

to exhaust the

vent channels

between Tyvek®

AtticWrapTM

and the roof

sheathing. Ridge

vent caps the

slot and permits

ventilation air to

exhaust.

Nail furring strips over rafters

STEP THREE

Nail roof sheathing over furring strips

STEP FOUR

STEP FIVE

Install successive courses of Tyvek® AtticWrapTM

Install sheathing with air slot at least 11/2 in. wide at ridge

STEP SIX

Fold Tyvek® AtticWrapTM over the ridge and over the membrane on the other side, then tape overlap

STEP SEVEN

8 9

FURRING INSTALLATION METHOD HIP AND VALLEY DETAILS

Install valley liner:Line the valley from the top of ridge to the eave

with a half

width sheet of

DuPontTM Tyvek®

AtticWrapTM.

Staple the

membrane taut

into the valley

center.

Cross-lap Tyvek® AtticWrapTM courses:Extend each Tyvek® AtticWrapTM course through the

valley center

and onto the

opposite roof

plane by at least

12 in. Where

the courses

overlap, seal

the top course

of Tyvek®

AtticWrapTM

to the bottom

course with

DuPontTM Tyvek®

Tape.

Attach furring strips to valley jack rafters:Cut and install furring strips over the valley jack

rafters ending

them 1 in. short

of the valley

center. This

leaves a 2 in.

air vent channel

in the valley.

Sheath over the

furring and the

2 in. space.

Cross-lap Tyvek® AtticWrapTM over the hip:Extend the sheets of Tyvek® AtticWrapTM from

adjacent roof

planes so that

they overlap

at the hip by

a minimum of

12 in. Tape the

overlap joint

with DuPontTM

Tyvek® Tape.

Finish the

cross-lap from

both sides

before installing

furring strips.

Install furring strips over hip jack rafters and sheathe:Cut and install furring strips on top of each jack

rafter up to the hip rafter. Furring strips should

extend to within 1 in. of the hip rafter. Cut and install

roof sheathing leaving a gap of at least 11/2 in. along

the hip for an air slot to exhaust the vent channels.

Ridge vent caps the hip slot and permits ventilation

air to exhaust. It may be necessary to apply blocking

to the tail of

the hip rafter

to support the

edge of the

roof sheathing.

Blocks may also

be installed to

the hip rafter

between jacks

to support the

edge of the

sheathing.

Line valley with half width sheet of Tyvek® AtticWrapTM

VALLEY HIP

FURRING INSTALLATION METHOD continued

STEP ONE

STEP THREE

Cross-lap Tyvek® AtticWrapTM courses

STEP TWO

STEP ONE

Cross-lap Tyvek® AtticWrapTM courses over hip

STEP TWO

Fasten furring strips over hip jacks

Nail furring strips over valley jack rafters

10 11

INTAKE VENT AND EAVE SEALING DETAILS - FURRING METHOD

Install blocking and nailers before wrapping the eaves with

DuPontTM Tyvek® AtticWrapTM. Subfacias may be installed before

or after Tyvek® AtticWrapTM is applied. Wrap the membrane

around the eave and back to the wall. Lap Tyvek® AtticWrapTM

over the housewrap by 6 in. and seal the joint with DuPontTM

Tyvek® Tape.

The Venting Drip Edge Eave details use specialty slotted drip edge as an air intake

VENTING DRIP EDGE EAVE DETAIL

Detail 2 uses a perforated soffi t or any soffi t vent product as an air intake

SOFFIT VENTED EAVE DETAIL 2

Detail 1 uses a continuous soffi t vent immediately behind the facia boardas an air intake

SOFFIT VENTED EAVE DETAIL 1

Wrap Tyvek® AtticWrapTM around the rafter tails and back to the wall

Venting drip edge

WRAP TIP Full rolls of Tyvek® AtticWrapTM are bulky to work with. Precut Tyvek® AtticWrapTM on the ground to make handling easier on the roof. Cut lengths of Tyvek® AtticWrapTM 12 in. longer than the roof length when using the Furring installation method. Add an additional 3 in. per rafter or truss bay when using the Rafter Cap or Drape methods.

Leave 11/2 in. space between facia and sheathing

Wrap membrane over rafter, attach to blocking

DuPontTM Tyvek® Tape DuPontTM Tyvek® TapeWrap membrane over rafter and subfacia, attach to nailer

Facia

Wrap membrane over rafter, attach to blockingContinuous soffi t vent

5/4 in. x 2 in. spacer

Facia

5/4 in. x 2 in. spacer

Continuous soffi t vent

DuPontTM Tyvek® Tape DuPontTM Tyvek® TapeWrap membrane over rafter and subfacia, attach to nailer

Facia

Continuous ventilated soffi t

Attach 5/4 in. x 2 in. spacers at rafter tail and along blocking

DuPontTM Tyvek® Tape


Standard drip edge Facia


Attach 5/4 in. x 2 in. spacersat rafter tails and blocking


Standard drip edge

Wrap membrane over rafter and subfacia, attach to nailer

Blocking

Blocking

Blocking

Solid soffi t

Nailer

Solid soffi t

Nailer

Nailer

Solid soffi t

Solid soffi t

Venting drip edge


Standard drip edge

Standard drip edge

10 11

The Rafter Cap method uses “U” shaped plastic

channels designed to fi t tight over the top of rafters. DuPontTM RafterCap creates air vent channels by holding

Tyvek® AtticWrapTM taut between the rafters about 11/2 in.

below the roof sheathing. Tyvek® AtticWrapTM wrinkles and

bunches where the surface plane of the roof changes at

rafter tails, hips, valleys and ridges. Extra care must taken

when detailing the membrane at these areas to maintain

open vent channels.

The Rafter Cap method can be combined with the Drape

method during installation.

The Rafter Cap method is compatible with any type of

insulation, including direct contact, provided the Tyvek®

AtticWrapTM membrane is taut between rafters.

Preparation: Select the Tyvek® AtticWrapTM eave detail

you wish to use. Install the required framing, including

subfacias, wall nailers, soffi t blocking and rafter blocking.

Apply the eave course of Tyvek® AtticWrapTM: Pre-cut one 6 in. piece of DuPontTM RafterCap for

each rafter tail. Snap a chalk line parallel to the eave

edge approximately 12 in. to 16 in. up from the rafter

tails. Roll out about 6 ft. of Tyvek® AtticWrapTM with

the integrated adhesive strip at the top. Align the

top edge of the membrane with the chalk line and

staple the end of the sheet to the fi rst rafter. As

one worker unrolls the Tyvek® AtticWrapTM, a second

worker places a rafter cap over each rafter. Nail or

staple the rafter caps securely to the rafters. Keep

the membrane

taut between

rafters and

aligned with

the chalk line.

Do not place

the rafter caps

above the

dotted overlap

line at the top of

the sheet.

Apply a full course of Tyvek® AtticWrapTM: After completing the eaves course, begin the fi rst

full course with the bottom edge of the roll aligned

with the dotted line on the course below. Slide

a full length DuPontTM RafterCap over the Tyvek®

AtticWrapTM and rafter, centering the rafter caps

between the

“overlap”

lines printed

on Tyvek®

AtticWrapTM.

Again nail or

staple the rafter

caps to the

rafters to hold

them securely in

place.

Staple the rafter caps to the rafters

Fasten the rafter caps to the rafters

STEP ONE

STEP TWO

Rafter cap

12 13

Air fl ow


DUPONTTM TYVEK® ATTICWRAPTM INSTALLATION USING RAFTER CAP METHOD

DuPontTM RafterCap holds Tyvek® AtticWrapTM

taut between rafters

Seal Tyvek® AtticWrapTM layers:Lift the bottom edge of overlying course and peel

the release liner from the integrated adhesive strip

on the course

beneath. Press

the layers

of Tyvek®

AtticWrapTM

together along

the integrated

adhesive strip to

create an airtight

seal.

Install roof sheathing over rafter caps: Snap a chalk line across the rafter caps as a guide

line for the top

edge of the

roof sheathing.

Install roof

sheathing

following the

local building

code nailing

schedule.

Install successive courses of Tyvek® AtticWrapTM and roof sheathing: Install the next course of Tyvek® AtticWrapTM using

rafter caps. Align the membrane with the dotted

overlap line on the previous course. Seal the joint

between the

layers with

the integrated

adhesive strip

and cover with

roof sheathing.

Continue the

sequence until

you reach the

ridge.


ridge and onto the other side. Seal the overlapping

edge with DuPontTM Tyvek® Tape. If the edge of the

membrane overlaps less than 10 in. over the ridge,

apply an additional sheet of Tyvek® AtticWrapTM

at least 20 in. wide over the ridge to protect this

vulnerable area. Cut and install short pieces of rafter

cap over the ridge between the rafters to prevent

loose Tyvek®

AtticWrapTM from

blocking the

vent channels.

Leave vent slot at ridge: Rip sheathing to leave an air slot at least 11/2 in. wide

at the ridge to

exhaust the

vent channels

between Tyvek®

AtticWrapTM

and the roof

sheathing.

Ridge vent

covers the slot

and permits

ventilation air to

exhaust.

Seal the layers of Tyvek® AtticWrapTM

together

Work off the roof sheathing to install successive Tyvek® AtticWrapTM courses

Fold Tyvek® AtticWrapTM over the ridge and tape overlap

Nail on sheathing ripped to provide a 11/2 in. vent slot

Install roof sheathing over rafter caps

STEP THREE

STEP FOUR

STEP FIVE

STEP SIX

STEP SEVEN

WRAP TIP If the roof pitch is greater than 5:12, install toeboards or roof staging along the roof sheathing as required by safety regulations.

12 13

FURRING INSTALLATION METHOD HIP AND VALLEY DETAILS

RAFTER CAP INSTALLATION METHOD continued

Drop valley rafter:Cut the valley rafter seat an additional 2 in. deep so

the valley rafter

rests lower.

Use a 2 in.

spacer block to

gauge the valley

jack installation.

Install Tyvek® AtticWrapTM through valley:Cross-lap the two sheets of DuPontTM Tyvek®

AtticWrapTM meeting at the valley by 12 in. minimum.

Leave enough slack in each layer to install the

DuPontTM RafterCap.

Cap jack and valley rafters:Apply a 1/8 in. to 1/4 in. strip of wood or plastic on top

of the valley rafter to hold the Tyvek® AtticWrapTM

in position and

keep the vent

space open.

Install rafter

caps over the

valley jacks

and staple any

loose Tyvek®

AtticWrapTM to

the rafters. Seal

the cross-lap

joints with

DuPontTM Tyvek®

Tape.

Drop valley rafter lower than jacks

DROPPED VALLEY RAFTER VENTING METHOD

STEP ONE

STEP TWO

Apply rafter caps over valley jacks

STEP THREE

Install Tyvek® AtticWrapTM through valley:Cross-lap the two sheets of Tyvek® AtticWrapTM

meeting at the valley by 12 in. minimum. Leave

enough slack in each layer to install rafter caps over

the jacks.

Apply rafter caps to jacks:Apply a DuPontTM RafterCap over each valley jack.

Tape the end

of the Tyvek®

AtticWrapTM

sheet to seal

the joint.

Install ValleyVent and sheath: Apply DCI Products’TM ValleyVent at the bottom of

each valley jack.

Place the thick

(three ply) end

of ValleyVent

to the valley

rafter and nail in

position. Apply

roof sheathing

over the valley

jacks and

ValleyVent.

Apply DCI Products’TM ValleyVent over jacks before installing roof sheathing

VALLEYVENT VENTING METHOD

STEP ONE

STEP TWO

STEP THREE

Apply rafter caps over valley jacks

Valleys can be vented two different ways. The valley rafter can be dropped by 2 in. to

create a vent channel or the valley jacks can be

vented laterally to an adjacent common rafter

bay by applying DCI Products’TM ValleyVent over

the lower portion of each jack.

14 15

INTAKE VENT AND EAVE SEALING DETAILS - RAFTER CAP METHOD

Cross-lap Tyvek® AtticWrapTM over hip:Cross-lap courses

of DuPontTM Tyvek®

AtticWrapTM a

minimum of 12 in.

across hip. Leave

enough slack in

each layer to install

rafter caps.

Install rafter caps: Cut and install DuPontTM RafterCap over the jack

rafters. Install short pieces of rafter caps over the

hip rafter between the jacks and inset staple any

loose Tyvek® AtticWrapTM to prevent it from blocking

the vent channel. Tape Tyvek® AtticWrapTM joints

with DuPontTM Tyvek® Tape.

Install roof sheathing:Cut and install roof sheathing up to the hip. Leave

a 11/2 in. minimum air slot between the panel edge

and the hip rafter to exhaust the vent channels.

Install blocking to hip rafter to support panel edges

if needed. Cut the bottom sheathing panels so the

lower one foot

laps over the

hip rafter for

support. Ridge

vent will cap

the vent slot

and permit

ventilation

air to exhaust.

HIP RAFTER VENTING METHOD

STEP ONE

Overlay Tyvek® AtticWrapTM from second roof plane onto the fi rst plane

STEP TWO

Apply rafter caps over jacks

STEP THREE


DuPontTM Tyvek® AtticWrapTM. Wrap the membrane around the

eave and back to the wall. Lap Tyvek® AtticWrapTM over the

housewrap by 6 in. and seal the joint with DuPontTM Tyvek®

Tape. With soffi t vented eave details, clinch staple the loose

Tyvek® AtticWrapTM between the rafter tails to prevent air

channels from being closed off.



The Soffi t Vented Eave details use soffi t vents or perforated venting soffi t

SOFFIT VENTED EAVE DETAIL



Nailer

Solid soffi t

Solid soffi t



Facia

Continuous ventilated soffi tDuPontTM Tyvek® Tape


Standard drip edge

Facia



Standard drip edge

Wrap membrane over rafter, attach to nailer

Blocking

Nailer

Blocking

Venting drip edge


Venting drip edge



Subfacias may be installed before or after Tyvek® AtticWrapTM is applied

Install subfacias after Tyvek® AtticWrap™ is applied

RAFTER CAP INSTALLATION METHOD continued

14 15

The Drape method requires no additional materials

like furring strips or rafter caps to be installed. Tyvek®

AtticWrapTM is draped between rafters leaving about a

11/2 in. space below the tops of the rafters. Using a jig,

the Drape method can be the fastest to install; however,

the eave, hip and valley details can be more time

consuming than the Furring or Rafter Cap methods.

When using the Drape method, extra care must be taken

to prevent the attic insulation from pressing against

the draped Tyvek® AtticWrapTM and closing off the vent

channels. This situation is most likely to occur along the

exterior wall plates or anywhere insulation comes into

contact with draped Tyvek® AtticWrapTM. To prevent this

problem, we recommend that rafter caps be installed

4 ft. up each rafter from the eave edge and in any other

locations where insulation may be installed in contact

with Tyvek® AtticWrapTM such as above knee walls.

Short pieces of rafter caps can also be installed over ridge

boards, hip rafters and the ends of valley and hip jacks to

prevent loose Tyvek® AtticWrapTM from blocking exhaust

vents.

Preparation: Select the Tyvek® AtticWrapTM eave detail

you wish to use and install the required framing including

subfacias, wall nailers, soffi t blocking and rafter blocking.

Complete all framing work before installing Tyvek®

AtticWrapTM.

DUPONTTM TYVEK® ATTICWRAPTM INSTALLATION USING DRAPE METHOD

Apply the eave course of Tyvek® AtticWrapTM: Snap a chalk line parallel to the eave edge

approximately 12 in. to 16 in. up from the rafter tails.

Roll out about 6 ft. of Tyvek® AtticWrapTM with the

adhesive layer at the top. Align the top edge of the

membrane with the chalk line and staple the end of

the sheet to the fi rst rafter. Drape the membrane

11/2 in. to 2 in. between rafters, using a small spacing

jig to achieve a consistent drape. Staple Tyvek®

AtticWrapTM to the top of rafters, then inset staple

the membrane to the inside edges of the rafters

11/2 in. to 2 in. down from the top. Space staples

2 in. to 3 in. apart. Inset stapling keeps the Tyvek®

AtticWrapTM

taut between

the rafters and

keeps the air

vent channels

from being

closed off when

insulation is

installed.

STEP ONE

We recommend that the fi rst two courses of

DuPontTM Tyvek® AtticWrapTM be installed with

DuPontTM RafterCaps when following the Drape

method of installation. Refer to rafter cap steps

1- 4 on pp. 12-13. The steps for installing the

Drape method using the inset stapling technique

instead of rafter caps are described in steps 1- 5 on

pp. 16-17. Where insulation comes in contact with

Tyvek® AtticWrapTM, rafter caps or inset stapling are

necessary to prevent the air vent channels from

being closed off.

16 17

Use jig to gauge drape depth

Build drape jig from blocks cut on the jobsite

2x2 13 in. long for 16 in. OC spacing,21 in. for 24 in. OC spacing

11/2 in. to 2 in. drape depth

2x3 18 in. long for 16 in. OC spacing,26 in. for 24 in. OC spacing

Air fl ow


drapes between rafters

Apply a full course of Tyvek® AtticWrapTM: After completing the eaves course, begin the fi rst

full course with the bottom edge of the roll aligned

with the dotted line on the course below. Staple

the top corner and roll out about 6 ft. of Tyvek®

AtticWrapTM across the rafters. Use a multi-block

spacing jig for consistent drapes between rafters

and to speed the installation process (previous page).

Staple Tyvek® AtticWrapTM to the top of the rafters

and inset staple 3 ft. in from the exterior wall. Be

sure to leave the

bottom 6 in.

loose for

sealing. Use

cap nails or

cap staples

during windy

conditions to

prevent Tyvek®

AtticWrapTM from

being blown

loose.

Seal Tyvek® AtticWrapTM layers:Lift the bottom edge of overlying course and peel

the release liner from the integrated adhesive strip

on the course

beneath. Press

the layers

of Tyvek®

AtticWrapTM

together along

the integrated

adhesive strip

to create an

airtight seal.

Install roof sheathing: Snap a chalk line across the Tyvek® AtticWrapTM as

a guide line for

the top edge

of the roof

sheathing.

Install roof

sheathing

following the

local building

code nailing

schedule.

Drape successive courses of Tyvek® AtticWrapTM: Drape the next course of Tyvek® AtticWrapTM across

the rafters. Align the membrane with the dotted

overlap line on the previous course and fasten.

Inset stapling is not necessary unless insulation will

come in direct contact with the membrane. Seal the

joint between

layers with

the integrated

adhesive strip

and cover with

roof sheathing.

Continue the

sequence up to

the ridge.

Drape Tyvek® AtticWrapTM between rafters with multi-block jig

Seal the layers of Tyvek® AtticWrapTM together

STEP THREE

Assemble a simple multi-block drape jig from jobsite scraps

3 ft. 2x2

Install successive courses of Tyvek® AtticWrapTM with multi-block drape jig

STEP FIVE

STEP FOUR

STEP TWO

Install roof sheathing over draped Tyvek® AtticWrapTM

1/2 in. plywood strip 18 in. long x 11/2 in. attached to 2x2 blocks 13 in. wide

DUPONTTM TYVEK® ATTICWRAPTM INSTALLATION USING DRAPE METHOD

16 17


ridge and onto the other side. Seal the overlapping

edge with DuPontTM Tyvek® Tape. If the edge of the

membrane overlaps less than 10 in. over the ridge,

apply an additional sheet of Tyvek® AtticWrapTM

at least 20 in. wide over the ridge to protect this

vulnerable area.

Install short

pieces of rafter

cap over the

ridge board (see

pp. 13, step six)

or inset staple

to the ridge

board to prevent

loose Tyvek®

AtticWrapTM from

blocking the

ridge vent.

Leave vent slot at ridge: Rip sheathing to leave an air slot at least 11/2 in.

wide at the ridge to exhaust the vent channels

between Tyvek®

AtticWrapTM

and the roof

sheathing.

Ridge vent

covers the slot

and permits

ventilation air to

exhaust.

Inset staple Tyvek® AtticWrapTM to the ridgeboard and seal the overlap with DuPontTM Tyvek® Tape

Drop valley rafter:Cut the valley rafter seat an additional 2 in. deep so

the valley rafter

rests lower. Use

a 2 in. spacer

block to gauge

the valley jack

installation.

Install Tyvek® AtticWrapTM through valley:Cross-lap the two sheets of Tyvek® AtticWrapTM


enough slack in the membranes to inset staple.

Inset staple jack and valley rafters:Apply a 1/8 in. to 1/4 in. strip of wood or plastic on

top of the valley rafter to hold Tyvek® AtticWrapTM in

position and keep the vent space open. Inset staple

the membrane to the valley jacks and valley rafter.

When available,

install pieces

of rafter caps

where the valley

jacks meet the

valley rafter.

Tape seams of

the the Tyvek®

AtticWrapTM

cross-laps with

DuPontTM Tyvek®

Tape.

Install and nail roof sheathing at ridge

STEP SEVEN

STEP SIX

DROPPED VALLEY RAFTER VENTING METHOD

STEP ONE

Valley dropped 2 in. to create air channel for venting jack bays

Apply a strip of wood or plastic on top of the valley rafter to hold Tyvek® AtticWrapTM in position and keep the vent space open

STEP TWO

STEP THREE

DRAPE INSTALLATION METHOD continued

Valleys can be vented two different ways. The valley rafter can be dropped by 2 in. to

create a vent channel or the valley jacks can be

vented laterally to an adjacent common rafter

bay by applying DCI Products’TM ValleyVent over

the lower portion of each jack.

18 19

HIP – DRAPE METHOD

Install Tyvek® AtticWrapTM through valley:Cross lap the two sheets of Tyvek® AtticWrapTM



Inset staple Tyvek® AtticWrapTM to jacks and valley rafter:Inset staple Tyvek® AtticWrapTM to the valley rafter

and bottom 12 in. of each valley jack. When

available, install

pieces of rafter

caps where

the valley jacks

meet the valley

rafter instead of

inset stapling.

Tape the end

of the Tyvek®

AtticWrapTM

sheet to seal

the joint.

Install ValleyVent and sheath:Apply DCI Products’TM ValleyVent at the bottom of

each valley

jack. Position

the thick (three

ply) end of

ValleyVent to

the valley rafter

and fasten it in

place. Apply

roof sheathing

over the valley

jacks and

ValleyVent.

VALLEYVENT VENTING METHOD

Cross-lap Tyvek® AtticWrapTM over the hip:Cross-lap the two sheets of Tyvek® AtticWrapTM

meeting at the hip by 12 in. minimum. Leave


Inset staple Tyvek® AtticWrapTM: Inset staple Tyvek® AtticWrapTM to the hip rafter and

the top 12 in. of each jack rafter. When available,

install short

pieces of rafter

caps over the hip

rafter between

the jacks and at

the end of the

jacks instead of

inset stapling.

Seal Tyvek®

AtticWrapTM joints

with DuPontTM

Tyvek® Tape.

Install roof sheathing:Cut and install roof sheathing up to the hip. Leave

a 11/2 in. minimum air slot between the panel edge

and the hip rafter to exhaust the vent channels.

Install blocking to hip rafter to support panel edges

if needed. Cut

the bottom

sheathing

panels so the

lower one foot

laps over the

hip rafter for

support. Ridge

vent will cap

the vent slot

and permit

ventilation air to

exhaust.

STEP ONE

STEP TWO

Inset staple Tyvek® AtticWrapTM to jack rafters

STEP THREE

Apply DCI Products’TM ValleyVent at the bottom of valley jacks

STEP ONE

STEP TWO

Inset staple Tyvek® AtticWrapTM to hip and jack rafters

STEP THREE

Install sheathing at hip to create vent slot

18 19

COMMON DETAILS USING DUPONTTM TYVEK® ATTICWRAPTM

DuPontTM Tyvek® AtticWrapTM can be directly sealed

to pipes or ducts that penetrate the roof plane

and do not carry heated exhaust. Some examples

are: bathroom exhaust duct, plumbing vent

stack, evaporator condensate drain, and electrical

conduit. Cut an ‘X’ slightly larger than the pipe or

duct in Tyvek®

AtticWrapTM

where it will

penetrate the

roof. Install the

pipe or duct. Lift

the membrane

towards the roof

sheathing and

tape it to the

pipe or duct with

DuPontTM Tyvek®

Tape. This

will help drain

water around

the penetration

should the roof

leak above it.

Tyvek® AtticWrapTM should not be attached directly

to metal pipes that exhaust heating appliances.

A 4 in. wide (minimum) collar should be affi xed

to the duct just beneath the rafter plane. Screw

and seal the

collar with an

intumescent

elastomeric

fi restop sealant

to the pipe.

Tape Tyvek®

AtticWrapTM to the

metal collar to

create an air seal.

NON-HEATING PIPE AND DUCT PENETRATION

Cut an ‘X’ into Tyvek® AtticWrapTM slightly larger than the pipe or duct

Tape Tyvek® AtticWrapTM to the pipe or duct

20 21

Seal Tyvek® AtticWrapTM to the metal collar or exhaust duct

METAL HEATING EXHAUST PIPE

INTAKE VENT AND EAVE SEALING DETAILS - DRAPE METHOD


DuPontTM Tyvek® AtticWrapTM. Wrap the membrane around

the eave and back to the wall. Inset staple the membrane

taut between the rafter tails. Lap Tyvek® AtticWrapTM over the

housewrap by 6 in. and seal the joint with DuPontTM Tyvek®

Tape. With soffi t vented eave details, clinch staple the loose

Tyvek® AtticWrapTM between the rafter tails to prevent air

channels from being closed off.



The Soffi t Vented Eave details use soffi t vents or perforated venting soffi t



Nailer

Solid soffi t

Solid soffi t



Facia




Standard drip edge

Facia

Continuous ventilated soffi tDuPontTM Tyvek® Tape

Standard drip edge

Wrap membrane over rafter, attach to nailer

Blocking

Nailer

Blocking

Venting drip edge


Venting drip edge



Subfacias may be installed before or after Tyvek® AtticWrapTM is applied


Install subfacias after Tyvek® AtticWrap™ is applied


Facia




Standard drip edge

Blocking

COMMON DETAILS USING DUPONTTM TYVEK® ATTICWRAPTM

Lap Tyvek® AtticWrapTM up onto sidewalls by a minimum

of 6 in. and staple. Lap housewrap over the Tyvek®

AtticWrapTM. Leave the bottom edge of the housewrap loose to insert roof fl ashing later.

ROOF TO SIDEWALL

SKYLIGHT OPENING 1

Tape DuPontTM Tyvek® AtticWrapTM to the housewrap,

such as DuPontTM Tyvek® HomeWrap®, at gable

ends. Lap Tyvek® AtticWrapTM over the gable end

rake wall and seal to the housewrap with DuPontTM

Tyvek® Tape. If the housewrap extends abovethe roof line, overlap

the Tyvek®

AtticWrapTM and tape along the gable rafter or top of the rake wall.

GABLE END (RAKE WALL)

There are two methods to seal Tyvek® AtticWrapTM

to housewrap on walls with rake overhangs.

1: Wrap the entire overhang in a similar fashion to

wrapping rafter

tails.

2: Cut Tyvek®

AtticWrapTM at

each horizontal

block supporting

the overhang

and wrap the

membrane

between them.

GABLE END (WITH RAKE OVERHANG)

Tape Tyvek® AtticWrapTM to housewrap along gable end

Cut Tyvek® AtticWrapTM and tape between horizontal framing to the housewrap

Lift up housewrap and staple Tyvek® AtticWrapTM to wall

Overlap vertical joints in Tyvek® AtticWrapTM by a

minimum of one rafter bay and two rafters. This

ensures a

mechanical

connection as

well as a taped

joint. Seal

the joint with

DuPontTM Tyvek®

Tape.

VERTICAL JOINTS IN TYVEK® ATTICWRAPTM

Overlap vertical joints in Tyvek® AtticWrapTM by a minimum of one rafter bay and two rafters

Skylight openings cut into the roof after Tyvek® AtticWrapTM

and roof sheathing are applied require extra detailing.

There are no provisions with this detail for cross-ventilation

of rafter bays that dead-end at the skylight.

Cut the skylight opening in the roof sheathing. ‘X’ cut Tyvek® AtticWrapTM and fold the fl aps out onto the roof sheathing

Tape pieces of Tyvek® AtticWrapTM at the corners to fi ll the void in the membrane

Trim the fl aps so 11⁄2 in. of Tyvek® AtticWrapTM folds onto the surface of the roof sheathing

Seal the Tyvek® AtticWrapTM edges to the roof sheathing using DuPontTM Tyvek® Tape or seal with elastomeric caulk and staple

SKYLIGHT OPENING 2

Skylight openings framed before Tyvek® AtticWrapTM and

the roof sheathing are installed are the easiest to prepare.

‘X’ cut out Tyvek® AtticWrapTM in the skylight opening Fold the fl aps back over the

rafters and headers, staple and trim excess membrane

Apply a 3 ft. length of DCI Products’TM RafterVent over each cripple rafter and trimmer rafters beginning 6 in. above and below the skylight opening to provide cross-ventilation between rafter bay air channels

Apply sealant around the perimeter of opening and bed the roof sheathing into it to form an airtight seal

Install and fl ash the skylight following manufacturer’s instructions

20 21

ROOF TO FACE WALL (VERTICAL WALL)

Where rafters terminate at a wall (as in the case of a shed roof) the air vent channels should be vented.

Use a vent product such as DCI Products’TM SmartVent. Install according to manufacturer’s instructions.

Install the roof sheathing leaving a 11⁄2 in. air space to vertical wall

22 23

COMMON DETAILS USING DUPONTTM TYVEK® ATTICWRAPTM continued

DuPontTM Tyvek® AtticWrapTM should not be attached directly to masonry chimneys. A 4 in. wide metal fl ashing or a metal collar should be affi xed just beneath the rafter plane to the masonry. Install

using masonry screws and seal with an intumescent elastomeric fi restop sealant to the masonry.

Tape Tyvek® AtticWrapTM to the metal collar to create an air seal

4 in. wide metal fl ashing or a metal collar

MASONRY CHIMNEY CONNECTION ALTERNATE EAVE DETAILS

There are numerous ways to seal the eaves with Tyvek®

AtticWrapTM and provide ventilation air intake. Several

common details follow each intallation method. The

following details depict the Rafter Cap method of installation

and can be modifi ed to suit the Furring and Drape methods.

Extend wall sheathing above plate to 11⁄2 in. below top ofrafters (or to the top of the rafters when using the Furring method)

Install Tyvek® AtticWrapTM fl ush with the end of the rafter tails but do not install rafter caps or staple the membrane to the rafters beyond the exterior wall line

Cut Tyvek® AtticWrapTM at the centerline of each rafter or truss up to the line of wall sheathing

Run a bead of elastomeric sealant on both sides of each rafter where it meets the wall sheathing

Fold the Tyvek® AtticWrapTM fl aps down to wall and embed in sealant

Tape the bottom edge of Tyvek® AtticWrapTM to the housewrap

Flashing

Vent

Lap Tyvek® AtticWrapTM up and onto the wall by a minimum of 6 in. and staple

Lap housewrap over Tyvek® AtticWrapTM

Exposed Rafter Tails

Apply sealant where collar meets masonry

Some styles of eave framing leave the rafter tails exposed.

Solid blocking installed between the rafters closes off the

rafter bays. Rip framing lumber for solid blocking 1 in.

narrower than the space between the wall plate and the top

of the rafter. Cut and install solid blocking between rafters.

Cut and install vent strip, 1 in. thick by 11/2 in. wide, over the

top of the blocking. Install roof sheathing.

Rip bevel on blocks to match roof pitch

Seal block to framing with caulkingInstall the membrane

fl ush with the blocks

Vented soffi t

Tyvek® AtticWrapTM bedded into sealant on blocks and sides of rafters

Vent strip

Vent stripTyvek® AtticWrapTM bedded into sealant on blocks and sides of rafters

Rip blocks to fi tSeal block to framing with caulking

Air Tight: A condition by which the perimeter of a space

is enclosed to minimize the air movement into or out of

the space.

Air Vent Channel / Vent Channel / Air Channel / Vent Space: These four phrases are used to identify

the space bordered by the rafters and in-between the

underside of the roof sheathing and the DuPontTM Tyvek®

AtticWrapTM. Air flows into the space at eave vents and

follows the space up to the exhaust vent.

Cap Nails / Cap Staples: A fastener with a broad

(1 in. or greater) plastic or metal disc that increases the

contact area to increase wind resistance to pulling out.

Diffusion: The flow of water vapor trough a building

component, caused by the vapor pressure difference

across the two sides of a component.

Eave: The edge of a steep roof that may or may not

project beyond the supporting wall. The eave may be

covered by roof sheathing, a facia and soffit.

Furring Strip: For the purposes of this guide, a furring

strip is a strip of lumber minimum of 1 in. thick by

11/2 in. located over each roof rafter and applied after

Tyvek® AtticWrapTM is installed over the rafters. Furring

strips are nailed to the roof rafters and they create the

vent space between Tyvek® AtticWrapTM and the roof

sheathing.

Integrated Adhesive Strip: A 2 in. wide strip of adhesive

pre-applied to Tyvek® AtticWrapTM and covered by a plastic

“release liner.” When the release liner is removed, the

sealant can bond to the underside of the overlying sheet

of Tyvek® AtticWrapTM forming an airtight seal.

GLOSSARY OF TERMS

Local Building Code: The building code that is enforced

in the jurisdiction where building is located.

Membrane: Typically a water resistive sheet, a term used

interchangeably with Tyvek® AtticWrapTM.

Radiant Barrier: A surface that reflects 99% or more of

the radiant energy back towards the energy source.

Radiantly Reflective: A low emissivity surface that

reflects most of the radiant energy back towards the

energy source.

Rafter Cap: A thin U-shaped channel that fits tightly

over a rafter or truss. DuPontTM RafterCap is used to set

the Tyvek® AtticWrapTM plane 11/2 in. below the decking to

create the air space for venting and drainage.

Ridge Vent: A class of roof vent products that is applied

over a slot in the roof sheathing left along the ridge or hip

of a house and permits air and water vapor to exhaust.

Sealed Attic: An attic designed to eliminate (or minimize)

the air flow into and out of the attic.

Subfacia: Solid lumber applied over the face of the rafter

tails that serves as a base to apply facia and soffit boards.

Common subfacia materials are 2x4 or 2x6.

Venting / Ventilation: The process of air flowing

through the vent channel between the roof sheathing

and the Tyvek® AtticWrapTM that carries away moisture

vapor and heat. Typically this is free air flow, not assisted

mechanically by fans or blowers.

22 23

Can I achieve a Sealed Attic by simply putting Tyvek® AtticWrap™ on top of the roof sheathing?

The Sealed Attic System relies on providing a

method for attic moisture vapor release through

the Tyvek® AtticWrapTM membrane and into an

active air space. This cannot be accomplished

with the Tyvek® AtticWrapTM installed over

the roof deck because conventional decking,

such as OSB and plywood, does not provide

adequate moisture vapor flow through.

Does the Sealed Attic System with Tyvek® AtticWrap™ work in all regions and climates?

Yes. The Sealed Attic System work in all

regions and climates, controlling moisture

within the attic space and improving the

thermal performance of the entire roof.

How does the Sealed Attic System work in hot and cold areas?

In both climates, the sealed attic eliminates outside

airflow into the attic space. The attic temperature

then tends to approach the temperature of the

living space rather than the outside temperature.

The heat flow between the attic and the living

space is therefore reduced along with the utility

cost. In a hot climate, the metalized “low-e”

surface of the Tyvek® AtticWrapTM membrane

works as a radiant barrier, cutting down the

radiant heat transfer from the shingles into the

attic space, keeping the attic cool. In turn, this

heat reflection by Tyvek® AtticWrapTM increases

the speed of the venting air in the channel right

beneath the roof sheathing, which helps to cool

down the OSB, felt and shingles. This overall

reduction of the heat load from the roof cuts

down the air conditioning needs of the home.

In a cold climate, the metalized reflective surface

of the Tyvek® AtticWrapTM membrane reflects the

radiant heat rising from the ceiling back into the

attic space. This keeps the attic warmer and

helps reduce the energy loss through the roof.

By increasing the attic temperature, the

Sealed Attic System with DuPontTM Tyvek®

AtticWrapTM helps prevent condensation,

mold and rot inside the attic.

Why is the metalized surface of Tyvek® AtticWrap™ installed facing down, to the inside of the attic space?

This is to keep the surface shinny by helping

prevent dust accumulation on the reflective

“low-e” surface. A Sealed Attic System

with a metalized surface facing down to

the inside of the attic is the best practical

solution for keeping the thermal performance

of the low-e surface effective over time.

Which installation method is preferred (furring strips, rafter caps, or drape)?

DuPont has developed three practical methods

to accomplish a Sealed Attic System with

DuPontTM Tyvek® AtticWrapTM. The selection of

one method vs. another will be influenced by

the builder’s preference, local framing practices

and local code compliance requirements.

Is the Sealed Attic System with Tyvek® AtticWrap™ applicable to all types of new residential roof designs that include valleys, dormers, hips and chimneys?

Yes. The Sealed Attic System is applicable to

all types of new residential roof designs, no

matter the roof size and complexity. DuPont has

developed extensive installation instructions to

deal with the complexity of most roofing details

such as valleys, hips, dormers and chimneys.

Can I use Tyvek® AtticWrap™ installation details not described in the installation guide?

Yes. There are too many roof configurations to

show all in one installation guide. When using any

detail to install Tyvek® AtticWrapTM, keep in mind

that there must be continuity of each vent channel

from intake to exhaust in order for moisture

vapor that diffuses through the membrane to be

carried away, and also for potential roof leaks.

FREQUENTLY ASKED QUESTIONS FOR THE SEALED ATTIC SYSTEM USING DUPONTTM TYVEK® ATTICWRAPTM

24 25

Is the Sealed Attic System with Tyvek® AtticWrap™ compatible with all types of roof coverings, including asphalt shingles, tiles, slates or metal?

Yes. The Sealed Attic System can be used with any

type of roof covering. Test data indicates that this

system will not adversely affect the life of the roof.

Does the Tyvek® AtticWrap™ installation method comply with OSHA requirements?

Installation of Tyvek® AtticWrapTM with conventional

harness and fall protection systems does comply

with OSHA requirements. When installing Tyvek®

AtticWrapTM on a roof, all local OSHA requirements

for working on roofs must be followed at all times.

Can Tyvek® AtticWrap™ be installed in a cathedral ceiling?

Yes. A Sealed Attic System with DuPontTM Tyvek®

AtticWrapTM is an ideal addition to a cathedral

ceiling assembly. Tyvek® AtticWrapTM holds the

insulation away from the vent channel and stops

air leakage from inside the house at the same

time. Always use the Rafter Cap or Furring

installation methods for cathedralized ceilings.

Will the installation of Tyvek® AtticWrap™ affect my ability to finish off part of my attic for living space?

The use of Tyvek® AtticWrapTM will improve your

ability to finish the attic and use it for living space.

In addition, it will increase the attic’s storage value.

Tyvek® AtticWrapTM keeps the attic drier and dust

free, while moderating the extreme temperature

differences experienced in a traditional vented attic.

Should I expect my attic to be warmer during the summer and colder during the winter?

No. Tyvek® AtticWrapTM will keep the attic

space temperature closer to the living space

temperature than will a traditional vented

attic. Tyvek® AtticWrapTM will make your attic

a “semi-conditioned” space, helping keep

it cooler in the summer and warmer in the

winter than a traditional open vented attic.

How does the Sealed Attic System with DuPontTM Tyvek® AtticWrap™ help prevent water damage caused by ice damming?

The Sealed Attic System helps reduce the heat

loss through the attic and roof during winter. This

keeps the roof surface cooler so ice dams aren’t

as likely to form in the first place. In the event an

ice dam does form, Tyvek® AtticWrapTM serves as

a secondary weather barrier to collect and safely

drain water that leaks through the roofing material.

Is the Sealed Attic System a totally new concept? How many homes have been built with this system?

The Sealed Attic System, pioneered by DuPont

during the last decade, was introduced in Europe in

1996. Since then, hundreds of thousands of homes

have been successfully protected with the Sealed

Attic System in several countries in Europe. In the

United States and Canada, DuPont has carried out

an extensive field testing program which involved

the construction and monitoring of 15 homes with

the Sealed Attic System across different regions

and different climates during the last three years.

Which official third party accreditation bodies have been involved in the field testing of the Sealed Attic System?

Part of the field testing program of the Sealed

Attic System has been carried out under the

supervision of Prof. Tang Lee from Calgary

University, Joe Lstiburek of Building Science

Corporation, Oak Ridge National Laboratory

and the Florida Solar Energy Center.

24 25

PRODUCT PROPERTIES

Properties Method DuPontTM Tyvek® AtticWrapTM

weather resistive barrier

Air Penetration Gurley Hill (TAPPI T-460) (sec/100cc)

Water Vapor Transmission ASTM E-96 Method B (g/m2 -24 hrs) (US perms)

Water Penetration Resistance AATCC-127 (cm)

Breaking Strength ASTM D-882 MD/CD (lbs/in)

Tear Resistance ASTM-1922 (Elmendorf) MD/CD (grams)

Surface Burning ASTM E-84 Characteristics Flame Spread

Indexed Smoke Developed Value

Data listed above was measured by an accredited independent laboratory. Individual roll results may differ due to normal manufacturing variations.

WARNING: DuPontTM Tyvek® is combustible and should be protected from a flame and other high heat sources. If the temperature

of DuPontTM Tyvek® reaches 750˚F (400̊ C), it will burn and the fire may spread and fall away from the point of ignition.

1100

185 27

200

26/29

4100/4800

5Class A

40Class A

BUILDING CODE REPORTSProduct has been submitted to ICC-ES with an

Engineering Report as an alternate method. ICC-ES

Evaluation Report is pending.

TECHNICAL SPECIFICATIONSDuPontTM Tyvek® used in construction products is

made from 100% flash spun-bonded high density

polyethylene fibers which have been bonded together

by heat and pressure, without binders or fillers, into

a tough, durable sheet structure. Additives have

been incorporated into the polyethylene to provide

ultraviolet light resistance. DuPontTM Tyvek® AtticWrapTM

has a thin aluminum coating on one side protected

with a thin acrylic layer. DuPont suggests that Tyvek®

AtticWrapTM be covered within 4 months (120 days) of

installation.

PRODUCT REPLACEMENTDuPont will replace any Tyvek® Weatherization

System product damaged during installation by

weather or normal handling if it is installed according

to procedures published by DuPont. If you have

any questions, call DupontTM Tyvek® Weatherization

Systems at 1-800-44-TYVEK.

WARNINGDuPontTM Tyvek® is slippery and should not be used

in any application where it will be walked on. In

addition, because it is slippery, DuPont recommends

using kickjacks or scaffolding for exterior work above

the first floor. If ladders must be used, extra caution

must be taken to use them safely by following the

requirements set forth in ANSI Standards 14.1,

14.2 and 14.5 for ladders made of wood, aluminum,

and fiberglass, respectively. DupontTM Tyvek® is

combustible and should be protected from a flame

and other high heat sources. DupontTM Tyvek® will melt

at 275°F (135°C) and if the temperature of DupontTM

Tyvek® reaches 750°F (400°C), it will burn and the fire

may spread and fall away from the point of ignition.

For more information, call 1-800-44-TYVEK.

NOTETo achieve greater potential, energy savings and

weather resistance, any tears, breaks, holes, etc.

created during normal construction should be repaired

by taping or patching with DuPontTM Tyvek® AtticWrapTM

weather resistive barriers. DuPontTM Tyvek® products

are weather resistive barriers, not the primary water

barrier (the outer facade is the primary barrier).

Contamination of any DuPontTM Tyvek® weather

resistive barriers and building papers with building

site chemicals which increase their wettability (e.g.,

surfactants) will adversely affect their water resistance

and therefore, their contribution to the overall water

resistance of the wall system. For superior protection

against bulk water penetration DuPont suggests a

system combining a quality exterior facade, a good

secondary weather resistive membrane and an

exterior sheathing, appropriate flashing materials

and details; and high quality windows and doors

with particular attention to proper installation of each

component. In a system where no exterior sheathing

is used and DuPontTM Tyvek® is installed directly over

the wall studs, exterior facade materials should be

selected to ensure maximum protection against water

intrusion. Careful workmanship and proper installation

of each component is very important.

DuPont believes this information to be reliable and

accurate. The information may be subject to revision

as additional experience and knowledge is gained. It

is the user’s responsibility to determine the proper

construction materials needed. Because conditions

are outside of our control, DUPONT MAKES NO

WARRANTIES, EXPRESSED OR IMPLIED, AND

ASSUMES NO LIABILITY WHATSOEVER AS TO

THE PERFORMANCE OF THE PRODUCTS FOR A

PARTICULAR USE. This information is not intended to

be used by others for advertising, promotion or other

publication for commercial purposes.

DuPont -Where Building Science and Technology Meet

Backed by over 200 years of science, DuPont works closely with the

world’s leading architects, building engineers and designers to create

products that help you build more beautiful, durable, energy-efficient

and healthier homes and buildings. We introduce timeless materials

that builders, contractors, dealers and homeowners depend on.

DuPont remains at the forefront of building science, and we’re

committed to finding new ways to create homes and buildings that

cost less to operate, are easier to maintain and provide more comfort

for people around the world. It’s all part of our commitment to

real-world, innovative solutions that can help everyone live a better life.

Strong Family of DuPont ProductsWhether you’re building new, remodeling, or re-siding, DuPont has

developed a family of weatherization systems products engineered

to address all your building needs. DuPont weatherization systems

products includes Tyvek® HomeWrap®, Tyvek® CommercialWrap®,

Tyvek® StuccoWrap®, Tyvek® DrainWrapTM, DuPontTM FlexWrapTM, DuPontTM

StraightFlashTM, Tyvek® Tape, Tyvek® Fasteners, and our newest miracles

of science, Tyvek® AtticWrapTM and Tyvek® ThermaWrapTM.

The DuPont™ Tyvek® Specialist NetworkThere are over 160 professionals who have the tools, training and

knowledge to help you build profits, quality and customer satisfaction.

Every time you work with a DuPontTM Tyvek® Specialist, you’re working

with someone who knows wall systems, R-values and construction

“best practices.” In short, when you have a question about materials,

techniques, codes or costs, your DuPontTM Tyvek® Specialist will provide

you with an answer. If your Specialist cannot answer you directly,

he or she will find someone who can.

For more information, Call us at: 1-800-44-TYVEKVisit us at: www.tyvek.comWrite us at: PO Box 80728, Wilmington, DE 19880-0728

BUILT BY SCIENCE

THE SEALED ATTIC SYSTEM WITH DUPONTTM TYVEK® ATTICWRAPTM PROVIDES A WEALTH OF BENEFITS

Helps cut overall cooling and heating

Regulates attic temperature

Acts as a secondary weather barrier

Enhances roof ventilation air flow

Channels moisture vapor

Improves insulation performance

©2005 by E.I. du Pont de Nemours and Company. All rights reserved. Tyvek® AtticWrapTM, The DuPont Oval

Logo, The miracles of scienceTM and DuPontTM are registered trademarks or trademarks of E.I. du Pont de

Nemours and Company or its affiliates.

For more information, Call us at: 1-800-44-TYVEKVisit us at: www.tyvek.comWrite us at: PO Box 80728, Wilmington, DE 19880-0728

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