A guy I know is building a new house, and has plumbed it all, and now, after it is all in, no gypboard yet, he is wondering about how to make the drains quiet. We toss around some ideas about wrapping the 3″ PVC lines with various kinds of stuff, spray foaming them, etc., and then come upon using sand. So basically, wherever there is a drain stack coming down inside a wall cavity, you use lumber or whatever, so as to make a smaller cavity for the pipe than a full stud bay (if you can) and then fill that cavity with dry sand as you go up with your second side of gyprock. Chop out a piece of rock up at the top so as to get that sand fill up there into most of the cavity, then patch and mud the hole. I know, he shoulda used cast iron, but hey, why won’t this work?
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Caulk or otherwise seal the bottoms/sides of the cavities so the sand won't sift out over time.
Do some computation to be sure the loading of the sand won't compromise the structure.
Consider the difficulties that will ensue if any of these areas need to be opened up for some reason.
Be wary of doing this immediately below an area prone to leaks (toilet, shower, etc) as the sand will absorb the water and "transport" it throughout the cavity, creating a substantially larger repair job.
You might consider wrapping the pipe with a heavy Butyl pipe wrap. Make sure the pipes don't contact the drywall or top / bottom plates or studs.
I find it helpful to be able to hear the water running. Many times I have stopped a running toilet and when my wife wants to know if kid x has taken a shower yet, I don't even have to get up from the lazyman to tell her yes, no or in progress.
But why not just opt for the rockwool that Holmes uses all the time. Personally, I would be more concerned with the bathroom walls than with the pipes themselves. I just don't care to hear someone taking a power dump...especially when the bathroom shares a wall with the kitchen...and if you are the one doing the dumping, you don't want to be sitting there holding back to try to make less noise. You want to really let it all hang out so to speak.
We usually just use cast iron for the drain stack. Wouldn't it be easier to change this section of pipe, assuming it is a simple straight shot from the second floor to basement, than do all the other stuff? Although the sand thing should work.
John
I say go for it. It will work and you will be the only house in the county with sand in the walls.
I've had pretty good results
I've had pretty good results wrapping PVC drains with lead sheet. Like used for roof flashing.
(I hope this shows up some where. It's my first post/reply since the ship hit the sand) I guess save = post?
>>>I know, he shoulda used cast iron, but hey, why won't this work?
I dunno, but with all the effort of setting up the sand treatment, wouldn't it be cheaper (and easier) just to get some Ferco fittings, CI pipe, and install it at strategic locations?
I second the recommendation for wrapping the pipes in lead sheet. The sand will work, but be harder to do and much potential trouble down the road. The lead will stay put, not absorb water, etc.
Use cast iron, or wrap pvc in Ice & Water Shield. Or fill chase with dense-packed cellulose.
I've thought of that as well,
I've thought of that as well, especially for sound deadening in existing drywall. Hey - it's fireproof!
The problem will be keeping the sand from pressurizing the bottom of the stud bay. If the wall has no doorways, you could just glue and screw on OSB to both sides before applying drywall.
If the drywall is already up on one side, that's tougher. Perhaps sheetmetal pulled away from the drywall, attached to the inside of the stud wall.
As I believe I said in the OP, if the sand fill deal gets done, there will be extra wood fixed into the bay so that the cavity size for a stack is no more than 6" wide.
I calculate the total fill in such a stack to be around 1.2 cubic feet, or at a density of 100 pounds per cubic foot (this from a web search, dry sand), that stack of sand will weight about 120 pounds.
As to future wall pokes, well, I am old, really old, Medicare old, earlybird specials old, and I cannot remember ever having to open up a wall or poke something in to fish a wire, or anything like that, in all the houses I've lived in.
I'd skip the sand and get the
I'd skip the sand and get the clay sheets intended for wrapping pipes and electrical boxes. I can never remember the brand name but I've bought them and other soundproofing stuff at specialty dealers. There is definitely not one near you.
If I were doing the sand, I'd mix in cement and make it into drypack... pack it around the pipe after one side of rock is on, screed it off like a wall tile bed. Might be easier, and you won't be finding sand on the floor for the rest of your life.
That's an interesting idea -
That's an interesting idea - would the drypack chemically interact with the pipe at all?
And that (drypack) is likely what the owner will do. He is an extremely capable builder, owner and operator for many years of a successful kitchen-bath-tile-design-and-installations biz, a mechanic capable of doing carpentry, cabinetmaking, furniture builds, stonework, tile, masonry of all kinds, mechanical systems including all plumbing and electrical work, all by himself.
I had this very problem with a drain pipe and hot and cold copper water supply lines running in a box across the ceiling in my bedroom. I wrapped the whole thing with fiberglass insulation. Packed it in there. Then covered the box with 5/8 fire code rock. Works great.
I placed this same question on various forums, and this solution, likely the best, came from one of those.
Pipes will be carefully wrapped in a "mass-loaded vinyl acoustical sheeting," all joints taped and sealed.
The sheet can be used sandwiched between studs and gypboard to greatly quiet sound transmssion through walls.
Source: http://www.acousticalsurfaces.com/noise_barrier/vinylbar_blowout.htm
I'm curious what shipping is
I'm curious what shipping is on a 230lb. package
Smaller quantities available here, and the tape is for sale, too.
http://www.soundisolationstore.com/products/mass-loaded-vinyl/2-pound-per-square-foot.html
A 4.5' x 10' sheet, weighing 90 pounds, would wrap more than three 3" PVC drainstacks coming through 8' high walls.
There is just no way to justify using Mass Loaded Vinyl (MLV) in this case. The stuff is way too expensive, difficult to use and unnecessary. The biggest culprit is usually the pipe contacting the framing. Make bigger holes in the top and bottom plates, avoid direct pipe contact with the studs and drywall. Install some light R13 fiberglass.
Be sure to use plexi for wall covering so you can see the termite farm. The kids'll love it.
k
Termites? We've none here as
Termites? We've none here as temps go way below zero each winter.
Did you miss the part where the sand is out and the pipes will get wrapped?