CHAPTER 6Structures and Components

Footing is located at the base of the foundation wall◦ It is always at the

bottom◦ It is stuffed into the

ground◦ The foundation is built

on top of the footing◦ Footing is supposed to

be 6 feet below frost line If it is less than 6 feet, you

will encounter problems

Footing

Foundation is the base upon which the structure is constructed◦ It holds weight of the

structure below frost line and prevents sinking

Foundations without sufficient sideway (lateral) support will deflect inwards

Foundation

A post (pillar) is a structural component that holds up the load of a beam down to the footings vertically.◦ Pillars are support columns, often located under

stairs and decks etc.

Columns/Posts

1. Moisture2. Out of Plumb

◦ Posts made out of plumb lose strength because they are incorrectly installed – they lean sideways and are not straight

3. Footing4. Rust

◦ Steel posts rust if the basement floods

5. Undersized◦ Post is not the right size and so it cannot support load

6. Fire◦ Fire damages steel posts faster than wood posts because

even though they don’t burn, they become weak

7. Secure to Beam◦ If post is not secured property to beam, structure will move

Possible Problems With Columns/Posts

Sills are pieces of wood that are between the foundation wall and brick wall◦ They have anchor bolts that keep them in place

Studs are built on top of sills◦ They make up the exterior walls

Problems with sills◦ Termites◦ Rot◦ Point loads

Sill crushes if there is too much pressure on 1 point◦ Anchoring

If sill not properly bolted to the foundation, it may shift resulting in the entire structure moving

◦ End bearing If joists are too short, the other sills may take additional load and

become damaged

Sill

Where is the anchor bolt used?◦ The anchor bolt is used to attach the sill to the

foundation walls

RECAP

Balloon framing is typically used in single-story bungalows

One stud (vertical wall framing) goes all the way from the foundation wall to the rooftop

The inside framing is built after the wall

Balloon Wall Framing

Platform framing is used in multi-story constructions (over 95%)

1 stud goes from foundation to 1st floor, and another from 2nd floor to roof

Walls built after inside framing

Platform Framing

Balloon = bungalow; platform = multi-story

Balloon = wall then joists; platform = joists then walls

Balloon v Platform Framing

Beams are long, structural components that carry the load of the wall and floor horizontally to the foundation

It is a horizontal frame in a house◦ Studs are vertical frames

Beams can be found either in the roof or basement

Beam

Joists are a type of horizontal wood members that support ceilings, roofs or floors◦ They are typically 2 inches thick

Joists are placed on edges and they get their strength primarily from their depth

In residential structures, you can choose between hardwood, carpet, laminate etc.◦ Under this material, you have the subfloor which carries

weight of moving objects such as people◦ Under subfloor, you have floor joists which are

horizontal pieces of wood to bridge and block joists from twisting

Joist

If joists are not bridged and blocked, they will move around freely◦ Both bridging and

blocking must be done together

Bridging and Blocking

Subfloors are used to carry live loads (people)

It is typically made from plywood and is located under the top layer/final floor

It is commonly known as pre-floor

Subfloor

Rafters are a kind of beam used to support the roof of a building

They carry the load of the roof to the outer brick walls

Rafters need support or they might break◦ This support is provided by collar ties & knee

walls◦ Collar ties carry load from one rafter to another◦ Knee walls support the bottom of the rafters and

are normally found in the attic

Rafters

Collar ties typically carry the load of one rafter to another rafter

Collar Tie

Roof trusses serve the same purpose as knee walls, collar ties and ceiling joists

They hold up roof shingles and sheathing and transfer the load of the roof to the outside walls

The bottom truss also performs function of supporting ceiling finish on which insulation sits

The main problem with trusses are the cut and truss uplifts

Trusses

A knee wall prevents the collar ties and rafters from falling apart by providing necessary support

Knee Wall

Where other than the attic can one find knee walls?◦ They are also commonly found in garages◦ But not all houses have a built-in garage◦ Attached garages are also common

RECAP

Roof sheathing is now done with wafer board panels, but till 1970s, wood planks and plywood were commonly used

Sheathing serves two important functions:1. Covering rafters2. Transmitting load of material (including

sheathing shingles, snow, ice and water)

Sheathing

Roofs protect houses from climatic conditions

A roof can be damaged by a number of factors including termites, condensation, and mainly abrasion caused by tree branches scraping roof shingles and Ice Damming (build-up)

Pitch is the angle (slope) of the roof

Roof

Flashings are used to join 2 dissimilar objects◦ They are used when there is a joint in materials or

when a material changes direction◦ Roof and chimney are joined together with flashings to

prevent leakage

They are made from galvanized steel

They are most likely to be found between 2 dissimilar objects/materials

They are least likely to be found between 2 shingles, since they are the same material

Flashings

The building code sets requirements for all kinds of construction, including basements◦ There needs to be sufficient structural integrity

and capacity

Basement leaks are typically intermittent, i.e. they occur after rainfall or melting of snow

Basement Leakage

1. Poor damp proofing around the house Allows water vapor to enter through concrete

2. Cracks in walls and windows3. Down spouts and eaves troughs are

damaged/cracked This prevents water from flowing away from the

basement, aided by an outside slope

4. The yard outside is sloped towards the walls of the basement

Causes of Basement Leaks

1. Fixing exterior slope away from the house2. Ensuring downspouts and eaves troughs

are installed properly and not broken 3. Window well covers4. Interior and exterior basement drainage

systems and sump pumps5. Improving surface drainage6. Damp-proofing exterior walls by covering

the footing joint or foundation7. Apply tar from grade level to footing to

increase protection against moisture

Solutions to Basement Leaks

1. Rust on posts, baseboard nails, furnace equipment or any other metallic objects either near or fixed into the walls

2. Mildew or mould3. Discoloration or stains on drywall, floor

panels or other interior finishes4. Moisture beneath the carpets or peeling floor

tiles

Real estate agents usually depend on both home inspections and property disclosure forms to determine the existence of water damage

Potential Signs of Leaks

If water leaks through cracks in the wall, it typically mixes with salt that is used for insulation purposes

The water eventually evaporates, leaving behind white salt crystals

Efflorescence

Drainage is a system of drains that are used to remove liquids◦ They may be natural or artificial ◦ It is typically a system of pipes, ditches, conduits

or other devices that allow water to run

External drainage◦ The Building Code identifies a number of granular

materials that must be used to drain water from below the foundation, and also where drainage disposal pipes must be situated

Drainage

Internal drainage◦ Includes footings placed below basement floor

level that lead to a waste sewage system or a sump pump

◦ Internal drainage is normally less desirable than external drainage because your main goal should be to prevent water from entering your property in the first place

◦ Internal drainage is a means of dealing with water once it has already entered the property

Drainage