Carpentry Skilled Trades 1201 Floor Framing
Floor Framing • In platform construction the floor framing serves several functions. It provides the basis for the Sub-floor (first layer of floor sheathing materials) and later the finish floor (second layer of floor sheathing material which is located directly under the floor covering).
Floor Framing The floor framing also provides support for the exterior walls of the house as well as a base for the interior partitions.
Floor Framing • Components of the Floor Framing # Girders # Column # Floor Joists # Bridging # Sub-floor
Floor Framing Types of Girders Girders are large horizontal members that are used to support other floor members that must span large distances.
Floor Framing • Built-up Girders: Usually made from three (min) pieces of 38mm by 200-300 mm stock nailed together-face to face. Girders of this type are preferred because they can be assembled on site form common building materials
Floor Framing • Laminated Wood Girder: Constructed of 19 mm stock bonded together to make up the required dimensions for the building. Girders of this design are assembled at a plant and shipped to site.
Floor Framing • I-Steel Girders: Prefabricated to specified length at a steel production mill. Girders of this type are expensive to purchase but are capable of spanning greater distances freeing up space in the basement for other usage
Floor Framing • Column Column are vertical members that are used to support girders that must span great distances. Several types of columns are used in house construction today.
Floor Framing • Steel Jack Post. Perhaps the most popular is the Steel Jack Post. These columns can be purchased at any hardware or building supply store for a reasonable price. Jack posts are less than 100 mm in diameter which means they can be concealed within the interior walls and are fully adjustable to match the height of the basement
Floor Framing • Built-Up Column A second type column is the Built-Up type. This column is constructed on site and uses 38 mm stock nailed together to build up the desired dimensions. Such columns must be carefully placed so as not to interfere will the installation of interior walls during the development of the basement living space.
Floor Framing • Floor Joists Floor joists are the main floor members that provides strength and rigidity to the building. Floor joists are usually constructed from 38 mm by 140, 184, 235, or 286 mm stock depending on the span of the building.
Floor Framing Spacing of the floor joists depends on the dimensions of the floor joists being used. The larger the lumber used the greater the spacing. Generally joist spacing can be 300, 400, or 600 mm depending on the floor load( how much weight it must support)
Floor Framing Bridging Small wood or metal members placed in a diagonal position between floor joists to restrain movement and twisting. Bridging members are spaced 2 100 mm.
Floor Framing Types of Bridging • Cross Bridging 19 x 89 mm strapping cut at an angle to fit between the floor joints and toe nailed into place using two 50 mm common nails.
Floor Framing • Solid Block Use the same dimensional lumber used in the floor joists. Short blocks are cut to fit between the floor joists and nailed in place using min. Three 75 mm common nails.
Floor Framing • Continuous Wood Strap Used as temporary bridging during construction. Use 19 x 38 mm strapping min. nailed to the underside of the joists using two 50 mm common nails
Floor Framing • Continuous Steel Strapping 3 x 25 mm mild steel band nailed to both the top and underside of the floor joists. Easy to install but can be more expensive than other bridging methods. Can be used as permanent bridging.
Floor Framing Subfloor Plywood or match lumber sheathing fastened to the floor joists to provide a base for the Finish floor. Thickness of the subfloor will vary depending on the spacing of the floor joists, but cannot be less than 12 mm thick if sheathing material is plywood
Floor Framing When constructing the subfloor a good practice is to glue the sheathing materials to the joist then nail (50 mm). This practice prevents squeaks from occurring.
Floor Framing • Finish Floor Placed on top of the subfloor to provide a smooth flat surface to lay assorted floor coverings