What is the best way to sound proof AB plumbing pipes?

December 2, 2008

Q. What is the best way to sound proof ABS plumbing pipes?


A. Plumbing pipes are often overlooked during home construction. My rule of thumb is to insulate all walls inside the home on all levels. Roxul Safe’n’Sound insulation is an excellent barrier to the transmission of sound and is also resistant to moisture and fire. This will give a tremendous sound deadening effect to all rooms not only water sounds through the pipes, but as well as privacy between rooms such as loud televisions, radios and bathrooms. Adding insulation around pipes on the inside walls can be done with little work and no vapour barrier is required as you are doing it for sound only.

Note: three-inch pipe in a 3-inch wall cavity will restrict the amount of insulation that you will be able to apply.

1. Locate the wall cavity encasing the noisy pipes.

2. Using a nail and hammer, punch the wall to locate studs on either side of noisy pipes.

3. Once you have located studs measure approximately to one inch from cavity side to identify centre of studs, make a mark.

4. Measure up from the floor 12 inches and down from the ceiling 12 inches and make a mark.

5. Using a four-inch level and holding it plumb on the stud centre marks, draw line up the stud to dissect a 12-inch mark from ceiling and down to dissect bottom mark from the floor.

6. Join all marks forming a rectangle on the wall this identifies the stud opening housing your noisy plumbing.

7. With a drywall knife and using a straight edge cut along all marks, apply pressure as you are cutting through gypsum board revealing pipes behind wall.

8. Fill the entire cavity with rock wool such as Roxul’s Safe’n’Sound insulation. Split batts in half to go around noisy pipes.

9. Replace piece of drywall (cut-out) and nail to studs, sand area along painted side of patch and drywall tape and fill.

10. Note: The drywall filler should extend four to six inches on either side of seam. This will feather the edge before priming and painting.

Some building contractors will use two-inch x six-inch wall studs when enclosing drainage pipes to enhance insulation cavity for sound proofing properties.