SMACNA Architectural Sheet Metal Manual
Peyton CollieProject Manager Technical Resources
SMACNA
Architectural Sheet Metal Manual 7th Edition
Completed update in early 2012 540 Pages (46 added) 188 CAD Drawings (29 new, many revised)
Drawings can be purchased separately 100s of editorial changes Added soldering and sealant guidance and
fascia and coping wind test to appendix
SMACNAs Manual Development Process And Procedures
Expertise is provided by a task force of SMACNA members with subject-specific experience
The task force guides SMACNAs technical staff in the development of content
Near-final drafts are distributed to local chapters for review by local, experienced contractors
Posted on SMACNA's website for 60-day public review
Some manuals go through the ANSI process using an additional canvass method of review
Technical Inquiries provide a source of feedback
Technical Inquiries
Customer technical support service Interpret SMACNA standards for:
Code officials Designers Members
Benefits of the service to SMACNA: Source of user feedback for future manual
upgrades Early indication of construction trends
Sheet Metal As An Architectural Element
Basic building material, long history of use Metals can be mixed to create totally unique
metalsand shapesfor unique buildings Metal roofs are enjoying a resurgence of use
notably, cool roofs Lowest-cost choice based on life cycle costing Many important metal elements are often
invisibleFlashing!
Benefits Of Sheet Metal Properly designed and professionally constructed
and installed by experienced contractors sheet metal elements can last for centuries
Sheet metal fits all green building materials measures, especially recycled content Recycled content: steel = 25%; copper = 43%; lead =
55%; stainless steel = 50% Energy efficiency per Florida Solar Research = light-
colored metal roofs VERY energy efficient Light weight and versatile
Soldered sheet metal joints do not require continuous maintenanceunlike ALL sealants
History Of Architectural Metals
First used by the ship building industrylead used in the 1500s with rolled copper use starting in late 1600s
New York City Hall used copper for roofing circa 1764 A copper roof was used on the rebuilt Old Senate
Chamber in 1819; replaced in a 1900 renovation The slate roof on the White House was replaced with
sheet iron in 1804 The copper roof on the Old Church of Christ in Philly
lasted from the 1830s to 1967 when the substrate failed Early metal roofs were batten-style or flat-seamed until
rolled tin production became common after the WBTS when standing seam came to general use
ASMM Contents Roof Drainage Design & Systems Gravel-Stop Fascia >> Roof Edging Copings Flashing Building Expansion Metal Roofs Wall Systems Louvers & Screens Miscellaneous Metal Structures Historical Restoration >> Much New Material Appendices >> Much New Commentary
Roof Drainage Design Roof Area Rainfall Intensity Metal Selection Gutter Type & Sizing Downspout Type & Sizing
Conservative compared to codes Expansion Allowances Fastening Method Selection Flashing Requirements
FIGURE 1-2 RECTANGULAR GUTTER STYLES10
11
Built-in Gutters
Subject of many Technical Inquiries Poses greatest risk of water intrusion Soldered or welded joints only Use high-quality membrane underneath Specific shapes address water freezing Attention to expansion allowances No single downspouts per roof section
FIGURE 1-5 ALLOWANCES FOR GUTTER EXPANSION13
Fastening Method Selection
Appendix for fasteners and soldering Screws best, SS best for treated wood
Commentary and illustrations throughout detailing clips, cleats, reglets
Solder old fashioned TI?s Solder permanent, sealants continuous
maintenance
Flashing Recommendations
Flashing section second largest in manual++ Incorrectly installed/designed flashing and
poor craftsmanship identified as major culprit at mold conferences Especially around windows! Roof edges and bottom of wall also problem areas
Techniques in manual superior to the caulk and pray approach Inset reglets, embedded metal, counter flashing, use
of clips and cleats, etc.
Gravel-Stop Fascia (Edge)
Chapter covers a multitude of fascia finishing methods for flat roof systems
Water should NOT be allowed to flow over the edge of built-up roofs!
Be careful with ladders and never step on the top (peak) of fascia edging
Another reason for controlled access
FIGURE 2-6 CAP FASCIA - INSTALLATION17
Copings The horizontal top surface most vulnerable
point for water to enter an exterior wall Water entering a wall travels horizonally
Copings provide a permanent water stop and reduce wall-related maintenance
Metal copings provide an attractive, finished appearance
Affected by new IBC wind uplift requirements
20
LOCKS AND SEAMS 22
Flashing Possibly the most important chapter! Time-tested (old-fashioned) methods to prevent
moisture intrusion Key component for the protection of the
structural elements and interior Use and importance of flashing was specifically
mentioned by several speakers at NIBS-BEC mold conferences
Soldered metal joints = no/low maintenance
FIGURE 4-4 COUNTER FLASHING SYSTEMS - INSTALLATION24
Building Expansion
Expansion and contraction = important design factor for larger structures/additions
Movement accommodated by specially-designed interlocking expansion joints
Proper width of expansion joints based on the total amount of expansion driven movement
FIGURE 5-3 BUILDING EXPANSION JOINTS ROOF AT GRAVEL STOP
26
Metal Roofing Early consultation with experienced sheet
metal contractor highly recommended Two types of metal roofs:
Non-structural requires continuous support Structural spans use intermittent supports
Compatibility of all materials and galvanic reactions need to be understood
Support/underlayment design critical Continuous enclosure barrier new challenge
in newer building codes & 90.1 NIBS BEC
FIGURE 6-5 STANDING SEAM ROOFS28
Standing Seam Roofs
Recommended for slopes of 1 in./ft or greatersealants not typically used on the vertical seam greater than 3 in./ft
Designers should consult local contractors for recommendations based on local conditions and experience
Evidence of declining uplift resistance as seam height increases
FIGURE 6-8 BATTEN SEAM ROOFS30
31
Batten Seam Roofs Recommended for slopes of 3 in./ft or greater Copper or aluminum metal Prominent ribs amplify the visual impact of roof Offers architects the widest range of individual
expression Size & shape of battens Intersecting battens at various angles Use in combination with other roof types and styles
33
FIGURE 6-11 BERMUDA TYPE ROOFS
34
Bermuda Roofs
Simulates the thick limestone shingles used on roofs in Bermuda
Used on contemporary designed structures Promotes a long, low look to the structure Can be used in conjunction with battens to
define separate planes Original function?
FIGURE 6-3 FLAT SEAM ROOFS36
Flat Seam Roofs Typically made from 20 x 28 sheets,
geometry is important Copper or dead soft stainless steel is
recommended Lock and seal all joints, solder joints on
slopes less than 3:12 Tapered-batten expansion joints required
on flat seam sections exceeding 30 feet
Appendices Metal Applications and Specifications Galvanic Corrosion Sheet Metal Roof Test Report Custom Fabricated Metal Roof Specs Moisture and maintenance of envelopes Fasteners Soldering Fascia and Coping Wind Tests
Galvanic Corrosion
Not well understood by many designers Proximity of metals in chart Passive SS simply means chemically
cleaned (changes characteristics) Contact not required, runoff can cause
corrosion Beware of HVAC condensate via copper
pipes to galvanized gutter
Galvanic Scale ANODIC/CORRODED END/LEAST NOBLE Zinc Aluminum Galvanized Steel Cadmium Mild Steel, Wrought Iron Cast Iron Stainless Steel, types 304 and 316 (active)* Leadtin Solder Lead Brass, Bronze Copper Stainless Steel, types 304 and 316 (passive) CATHODIC/PROTECTED END/MOST NOBLE*Chemically cleaned usually with acidic solution
Sheet Metal Roof Test
UL Standard 580/Factory Mutual
Static Water Penetration
Dynamic Water Penetration
Structural Load
Deflection
Not Wind Resistant
IBC Section 1504.5
Edge securement for low-slope roofs. Low-slope membrane roof system metal edge securement, except gutters, shall be designed and installed for wind loads in accordance with Chapter 16 and tested for resistance in accordance with ANSI/SPRI ES-1, except the basic wind speed shall be determined from Figure 1609.
SPRI STANDARD ES-1
Edge membrane retention SPRI Test RE-1 Force required to separate membrane from
edge device, strength of membrane key Edge flashings SPRI Test RE-2
Force required to pull edge device off wall Copings SPRI Test RE-3
Force required to lift coping off wall
How Compliance is Met
Designer calculates and specifies minimum wind pressure (uplift)
Metal element must be manufactured or custom fabricated to tested design
Metal element must be installed using methods according to tested design
Metal element is inspected as fabricated and installed as per a tested design
Fascia Pulloff Testing (Wind Uplift)
Pull Numbers
ASTM Standard Language
In applying the results of tests by this test method, note that the performance of a wall or its components, or both, may be a function of fabrication, installation, and adjustment.
SPRI Std Does NOT Require Third party certification of construction
This provides no assurance correct element was installed or installed correctly
Any type of stamp indicating compliance on compliant elements This was discussed at length during the
development of the SPRI standard and determined to have no merit because it provides false sense of compliance
Contractors Qualification Checklist
Jointly developed by AIA & SMACNA Design limited only by imagination, not contractor skills Positive impacts on project completion schedule Ensures proper installation, increases architects options
for future creativity Qualifies contractor based proven experience record Assures two most important characteristics of
architectural elementsaesthetics & water tightness
QuestionsCommentsSuggestions