Lumber Grades

Each piece of lumber is examined and assigned a grade depending on its physical characteristics. In addition to visually graded lumber, machine-stress-rated (MSR) lumber is available in Canada. MSR lumber is identified in grade stamps by its structural properties and, for most wood-frame construction purposes, is independent of species. Many softwood lumber species in Canada are harvested, milled and marketed together. Those having similar properties that enables them to be used together easily...

Installing Roof Sheathing

How Nail Roof Sheathing

When plywood or OSB is used for roof sheathing, it is laid with the face grain at right angles to the framing Fig. 68 . Sheathing-grade structural wood panels SWP is used for this purpose. To obtain a good tie across the roof framing, the end joints of the panels should be staggered on the framing members. The edges of the panels should be separated by at least an ' s in. 2 to 3 mm to prevent buckling when minor expansion occurs during wet weather. The thickness of the plywood, OSB or...

Typical House Construction Process

Due to the wide variety of homes in terms of style and size, and the differences between professional builders and the do-it-yourselfer, it is difficult to say exactly what is a typical house construction process. Many factors apply, such as whether a single house or a whole subdivision is being built, as well as other factors such as weather, site conditions and the availability of labour and materials. The description of the typical house construction process which follows is based on the...

Insulation Of Walls

Fibreboard Sheathing

With normal 2 x 4 in. 38 x 89 mm stud framing, the maximum effective thermal resistance that can be achieved by filling the cavity with batt-type insulation and using normal finishing, sheathing and cladding materials is approximately R-12 RSI 2.1 . By careful selection of the sheathing and cladding, this can be extended to about R-13 RSI 2.3 . This assembly, while suitable for seasonal buildings, does not meet current code requirements. Going beyond this level requires special measures. One...

Insulation Of Floors

Floors over unheated crawl spaces or over heated or unheated garages should be insulated. Where there is no finished ceiling on the underside of the floor, some material must be added to support the insulation. For friction-fit type batts or for rigid insulation Fig. 120 , wire lath or chicken wire tacked to the bottom of the joists may be the most economical method. For loose fill-type insulation Fig. 121 , the support must be provided by a material which is solid to prevent the insulation...

Stairway Design

Stairways may have a straight, continuous run without an intermediate landing, or they may consist of two or more runs with changes in direction. In the best and safest practice, a landing is introduced at any change in direction, but the turn may be made with radiating treads called winders. The length or width of any landing must not be less than the width of the stairs. Stairs must be at least 34 in. 860 mm wide measured face to face of wall. The diagrams in Figure 99 show different types of...

Planning Ahead

Trimmer Studs Jack Studs Lintel

Providing the Required Effective Thermal Resistance Code requirements for minimum levels of effective thermal resistance in wall and other building assemblies depend on climatic conditions and the type of energy source used for space heating. It is important to understand the difference between the nominal and effective thermal resistance of insulated building assemblies. The nominal thermal resistance refers to the thermal resistance rating of the insulation which is installed. For example, a...

Balloon Construction

Balloon framing differs from platform framing in that the studs used for exterior and some interior walls are continuous, passing through the floors and ending at the top plates which support the roof framing. Since the connections between the floor joists and studs in balloon framing do not lend themselves to pr fabrication or easy assembly on the site, this method of framing houses is rarely used. However, some of the techniques involved in balloon framing may be used with the platform...

Wood Shingles and Machinegrooved Shakes

Dormer Siding Clearance

Wood shingles or machine-grooved shakes are sometimes used for wall covering. A large selection is available, including special wall shingles in Comer treatment of siding A corner boards B mitred corner C metal corner D siding return on main roof, showing, corner boards. Mitred or metal comers can also be used on the return, depending on the design. siding to have 2 50 mm clearance above shingles lengths of 16, 18 and 24 in. 400, 450 and 600 mm , factory-painted or stained. Shingles are usually...

Flashing

Flashing is provided, where necessary, to prevent the entry of water through joints between materials. Proper installation of flashing is important, as is the selection of the most suitable materials for each specific location. The minimum recommended weights and types of materials for flashing are shown in Table 31. Aluminum flashing should be Isolated from masonry or concrete or coated with an impervious membrane to reduce the possibility of corrosion. Flashing should be used at the junction...

Checking Back

Sill Plate Beam Detail

Before selecting a floor-framing system, it is important to check back to determine how the lloor system will be connected to the foundation wall. When the sill-plate method of foundation wall and joist connection is employed, the sill plate must be securely anchored to the foundation wall. This is normally done using sill anchors embedded in the top of poured concrete walls, or in the top course of concrete blocks having their holes filled with concrete. The method of connecting the floor...

Builtup Roofs

Built-up roof coverings are installed by roofing firms that specialize in this work. Roofs of this type may have three or more layers of roofing felt. Each layer is mopped down with tar or asphalt, the final surface being coated with the same material. The surface is then covered with gravel embedded in the asphalt or tar or with a cap sheet. This covering provides ballast and protection from the sun's ultraviolet radiation. It is important to note that coal tar products and asphalt products...

Floor Joists

Joist Lapping

Joists are selected to meet strength and stiffness requirements. Strength requirements depend on the loads to be carried. Stiffness requirements, on the other hand, are intended to limit cracking of ceiling finishes under live loads and, even more important, to limit vibrations from moving loads, often a cause of annoyance to occupants. Wood floor joists are generally 2 in. 38 mm thick and either 6, 8,10 or 12 in. 140,184, 235 or 286 mm deep. The size depends upon the loading, length of span,...

Masonry Veneer

Brick Tied Sheathing

If masonry veneer is used for the exterior cladding of above-grade walls, the foundation must include a supporting ledge or offset wide enough to allow a space of about i in. 25 mm between the masonry and the sheathing paper Fig. 84 . A base flashing should extend from the outside face of the wall over the top of the ledge and at least 6 in. 150 mm up the wall behind the sheathing paper. Corrosion-resistant metal ties, nailed to the studs and embedded in the mortar joints between the masonry,...

Warmair and Ventilation Systems

Normally, wall studs and joists are located so that they do not have to be cut to install heating ducts. When ducts must pass up through a wall to heat the room above, the top and bottom plates must be removed at these points, and the ducts are then fitted between the studs. When a partition is supported on doubled floor joists and a heating duct is to go in the partition, the joists are ordinarily spaced apart, with blocking, to allow room for the duct. This eliminates the need to cut framing...

Lumber Siding

Lumber siding should be sound and free of knot holes, loose knots, checks or splits. Easy working qualities and freedom from warp are desirable features. The species most commonly used are cedars, pines and redwood. It has also become more common to use pressure-treated lumber for siding. Pressure-treated siding may be manufactured from pine or other species. The moisture content of the siding at the time of application should be the same as it will experi- sheathing sheathing membrane vertical...

Top Plate On Dormer

What Double Header Construction

The tables for sizing roof members assume that a conventional roof covering. such as asphalt shingles, cedar shakes or lightweight metal roofing, is being installed. Some roof coverings, such as terra cotta tile, are much heavier and hence the roof members must be sized accordingly. The following points should be considered when sizing roof framing members supporting heavier than normal roof coverings. Obtain the unit weight pounds per square foot or kilograms per square metre from the...

Insulation Of Truss Or Raftertype Roofceilings

The thicker batts now available for insulating roofs are made in widths equal to the full centre-to-centre distance of standard roof framing. The lower portion is slightly compressed when installed between the framing, but the upper portion retains its width and covers the tops of the framing, thus reducing heat loss through the framing. Eave details to avoid blocking ventilation A suggested detail with ordinary truss heel joint B alternative design with raised truss heel joint. Loose-fill...

Beam And Joist Installation

Metal Plate Bolt Wood Beams Together

The simplest method of beam and joist framing is to have the joists on top of the beam Fig. 31 , in which case the top of the beam is level with the top of the sill plate Fig. 30 . This method is used where the basement must have adequate headroom below the beam. Where more clearance under a wood joist is desired, joists may be supported by joist hangers or other structural connectors attached to the beam. In lieu of joist hangers, the National Building Code allows joists to be supported on...

Ceiling And Roof Framing

Roof Framing Examples Double Pitch

There are two basic types of roofs pitched and flat and each type has many variations. The slope of a roof is expressed as a ratio of rise-to-run with the vertical component, or rise, always being shown first. There are two conventions for expressing the slope of a roof imperial and metric. The imperial convention is based on the use of a framing square, and the run is always expressed as 12, based on 12 inches to a foot. For example, a roof with a slope of 450 is expressed as a 12 12 pitch. A...

Pitched Roofs

Attic Trusses Temporary Bracing

Roof trusses are most often pre-assem-bled, although they can be constructed on site. Pitched roofs can also be stick-built, although this is a Types of prefabricated roof trusses. time-consuming process. Of the pitched roofs, the gable roof is the simplest to construct, especially with the use of lightweight roof trusses Fig. 48 . Other configurations, such as the hip roof and L-shape roof, though more complex, can also be framed with trusses Fig. 49 . Pre-assembled roof trusses offer many...

Framing Details For Plumbing Systems

Washbasin Flange

The installation of the plumbing system usually begins after the framing. This initial work is called rough ing-in. It includes putting in the plumbing vents and drains and all the hot and cold water piping which will be enclosed in the walls and ceilings and under the basement floor. Piping in outside walls should be insulated. Since the bathtub must be put in before the wall finish can be applied, bathtub installation is usually included in roughing-in. Plumbing fixtures and accessories are...

Flat Roofs

Flat Roof Construction

Flat roofs are generally less practical and less durable than pitched roofs, especially in heavy snowfall areas. They are sometimes used to cover extensions of the main house and in combination with upper floor decks. Carports and garages are frequently covered with a flat roof. In flat-roof construction where rafters also serve as ceiling joists, the term roof joist is used. The size of these roof joists is established on the basis of both roof and ceiling loads. See Tables 24 and 25. Rafters...

Stair Design Terminology

Mitre Stringer

The following are terms often used in stair design Figs. 96 to 99 Baluster Vertical member in a guard placed between the handrail and the tread in the open portion of a stairway, landing or balcony Fig. 96D . Effective Depth The portion remaining after the stringer has been cut out or ploughed to fit the treads and risers Fig. 97 . Guard Protective barrier, with or without openings, placed alongside the open portion of a stairway, landing or balcony. Handrail A rail running parallel to and on...

Footings Foundations And Slabs

Concrete Footing

Footings receive the house loads through posts or foundation walls and then transmit these loads to the soil. The type and size of footings should be suitable for the soil conditions, and located far enough below ground level to be protected from frost action. Frost action can also be avoided by providing good drainage around the foundation to direct water away from the building. In some cases, insulation can be used to provide frost protection for shallow foundations. Competent design is...

Insulation Of Joisttype Roofceilings

When the ceiling finish is applied directly to its bottom surface, a roof framing member is called a joist rather than a rafter. This type of construction is found in flat roofs and some cathe dral or sloping ceilings. When such roofs are insulated between the ceiling and the sheathing, condensation problems can occur because the space between the insulation and the sheathing is divided into small compartments which are difficult to ventilate. Thus, any moisture which Insulating joist-type...

Foundation Wall And Joist Connection

Floor Joist Concrete

The two general types of floor joist construction used over the foundation wall conform either to platform or balloon-frame construction. Platform framing is by far the most common type used. In platform framing, two methods of wall and joist connection are used and are generally referred to as the sill-plate method and the joist-embedded method. This method can be used with either concrete or concrete block foundation walls. It consists of a wood sill plate anchored to the foundation wall Fig....

Stucco Finishes

Stucco generally consists of a mixture of Portland cement and well-graded sand, with hydrated lime added to make the mixture more plastic. An alternative stucco mixture calls for replacing the lime with masonry cement. Table 37 lists the proportions for the preparation of these two stucco mixes. Other proprietary stucco mixes are available. Their formulations will vary depending on the manufacturer of the mix. Applied in three coats two base coats and one finish coat , the stucco is held in...

Eave And Cableend Intersections

Eave and gable-end intersections depend largely on how the eave projection is finished. Figure 93 A through C shows three types of commonly used intersections. Figure 94D shows an example of an aluminum soffit. Aluminum can be used for all three types of intersections shown. Where a sloped soffit is used at the eave projection, the soffit of the gable-end projection is carried through on the same plane as the eave soffit Fig. 93B . Where a horizontal soffit is used at the eave projection, the...

Eave Projection

The eave overhang gives some protection to the side wall and connects the roof and wall. Soffits are usually closed in with pre-finished metal or vinyl panels or 1 4 in. 6 mm sanded plywood nailed at 6 in. 150 mm on centre along the edges and 12 in. 300 mm at intermediate supports. The exterior finish is then butted up to the underside of the soffit. A fascia board added as a finished covering for the rafter header usually extends about 1 2 in. 12 mm below the soffit covering to form a drip...