Framing for Plumbing systems

The installation of the plumbing system usually begins after the framing is complete. The initial work is called “roughing-in” and includes installing plumbing vents and drains and all hot and cold water piping that will be enclosed in the walls and ceilings and under the basement floor. Since the bathtub must be installed before the wall finish can be applied, bathtub installation is usually included in roughing-in.

Figure 151

Kitchen and bathroom in proximity for minimum pipe length. Framing for Plumbing systems

Wherever plumbing reduces insulation or affects an air barrier, provide additional insulation on the exterior and ensure that the air barrier is continuous and uninterrupted.

Connect plumbing fixtures and accessories after the installation of the interior finish has been completed. Figures 151, 152, 153 and 154 show typical plumbing arrangements for wood-frame construction. Check local or provincial plumbing requirements. When 75 mm (3 in.) copper or plastic piping is used, the plumbing stack wall may be made of 38 × 89 mm (2 × 4 in. nominal) material (Figure 154).

Figure 152

Washbasin and bathtub fixtures. Framing for Plumbing systems

Figure 153

Toilet fixture. Framing for Plumbing systems

Figure 154

Venting for plumbing.

Seal around the ceiling penetration to maintain air barrier continuity and prevent air leakage into the attic space (Figure 155). A flexible sheet rubber or neoprene flange placed around the vent stack provides an effective, flexible air seal. It can also move with the vent stack as it contracts and expands with the heat of air within it. Where soil stacks or large pipes must run horizontally at right angles to the joists, it will be necessary to frame out the joists. To do this, headers are installed between the joists (Figure 156). Alternatively, services are suspended below the joist and enclosed in a bulkhead or dropped ceiling chase.

Figure 155

Sealing a plumbing vent below an attic.

Figure 156

Framing for soil-stack pipes.

Source : Canada Mortgage and Housing Corporation (CMHC)