Installing pipes in exterior walls should be avoided. … Air-sealing the wall cavity will help prevent cold air from flowing around the pipes and causing freeze problems. All hot and cold water supply pipes should be insulated, which can save energy by minimizing heat loss through the piping.
Yes, plumbing CAN be placed on exterior walls. However, it is NOT recommended. This includes any waste and venting pipes, as well as main waterlines. When placed on an exterior wall, any of these may freeze, especially if it’s a water line.
Can You Install Plumbing Pipes on outside Walls? – Remodeling Tips
Tiny House Plumbing Update: Interior vs. Exterior Walls
Waterlines in a 2x4 exterior wall
Frequently Asked Questions
Do you put insulation behind shower walls?
The insulation behind the tub or shower should be equivalent to the insulation in the rest of the exterior walls and should be covered with an air barrier of cement backer board, rigid foam insulation, or non-paper-faced drywall that is sealed at the edges and seams to provide a continuous air seal.