The walls which have plumbing systems like pipes, air ducts and other mechanical elements installed are known as plumbing walls or wet walls. The walls in a bathroom or the wall behind a sink are plumbing walls. These walls have to be thicker than normal walls or dry walls as they have piping systems installed in them.
How thick is a plumbing wall? Discussed below is the thickness of walls of several plumbing systems.
The pipes which pass through cinder or concrete floors and walls must have a thickness of 0.025 inch in the least. Walls which have a protective sheathing for protection against external corrosion should also have the same minimum thickness.
An external piping system for water supply should be installed more than 6 inches below the frost line at the least and it should not be installed 12 inches below the grade. Soil, waste and water pipes must not be installed on the exterior of a building and in the attic spaces. Such pies should not be installed in a place where they may be subject to freezing unless sufficient provision is made to keep the pipes from being frozen.
Walls which are two-by-six must have at least 5 inches width in order to provide sufficient space for accommodating the air ducts, drainpipes, and other required elements. If the drywall is added on both the side of the wet wall then the two-by-six wall becomes 61/2 inches wide in the least.
For a normal plumbing wall, it should be about 6 inches in its breadth. For cast iron plumbing, the cast iron drain should be 4 5/8 inches in diameter. If the plumbing system uses plastic pipes, then a 4-inch wall will be sufficient. It takes almost double the thickness of a drywall to fit in the plumbing system inside the wall.