Hello all. We are building a house where having supply pipes run along one exterior wall is unavoidable. It is for a laundry room where we’ll have a dog wash and a washer. The exterior walls are 2×6 (R19) but I still want to bring the pipes into the thermal boundary. My thought is to fur the wall out another 3.5 inches and run the pipes through these 2x4s. We’ll even turn this into a feature by running them only 3′-4′ high, putting tile along the top and calling it a shelf. It will be behind the washer so it will add some convenience.
The question is whether to put drywall between the real exterior wall and the furring wall to ensure the pipes are inside the thermal boundary. Also, should I hide vent or something to keep an opening between the wall cavity and interior space.
Any thoughts would be appreciated.
-Jonathan
Replies
bump
You are wise to keep the pipes on the warm side. Furring out is a good idea, but you don't need to go 3½ inches. Just a 2 x 2 would be enough, unless you do want the shelf.
You don't need the drywall behind the pipes; all you need is the pipe on the inside of the vapor barrier. The drywall adds very little insulation value and I can't think of any other reason to put it there.
Fire stoping is a good reason . and it is cheap insurance.
It would be on the wall anyway, just in front of the pipes.
But wouldn't that be an open cavity with no insulation ? up against a thin VB . DW is cheep enough that I would put it all the wayon the inner wall.
In theory just a vapor barrier (that will also be an air barrier) is sufficient. The drywall would add some thermal mass, though, and isn't a bad idea. It also helps assure that the vapor barrier isn't damaged during the plumbing installation.
Also, it is a good idea to have the bump-out is vented a little bit. Doesn't need to be a lot, but enough to assure a touch of airflow through.
Re the depth of the bump-out, if you're going to have it at all, might as well be at least 3", preferably 4-5, to make a decent shelf. Or put a 1x6 (maybe plastic decking, or a piece of simulated marble) on top to make a decent shelf.