We’re looking for any advice about dampening sound in pvc drain pipes.
We’re building a new house. My husband is sensitive to house sounds, and the pvc drain pipes from the 2nd floor master bathroom and family bathroom will run over the kitchen ceiling and then down a wall to the basement. Any ideas about dampening the sound? advice?
Thanks in advance,
Debbie
Homeowner
Learn how to patch drywall above a fiberglass shower without totally redoing everything.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
Install cast iron pipe where noise is a problem.
Oh you don't have to be sensitive to hear this, it's the great disadvantage of PVC pipe. Wrap the joist bay in fiberglass insulation or switch to cast iron DVW.
I'm just "shooting from the hip" on this, but if you had some scraps of carpet or carpet pad, wrapping the pipe with them might dampen the noise. Maybe foaming the bays that contain the pipes would also help.
Cast iron was used here. I dare you to hear waste or the roof drains. (flat roof)
Cast iron is definitely the way to go. Regardless, have a meeting of the minds with your GC, plumber and lead carp. There are ways to minimize pipe sounds, and sound transmission in a structure, through advance planning and mitigating measures. For instance, instead of having the pipe run across the kitchen ceiling, maybe it can be dropped straight down to the basement, then run over to the main DWV.
Even in plastic drain pipes, annoying turbulence and drippin sounds can be minimized by the use of "long sweep 90" fittings wherever a horizontal run changes direction, and wherever a vertical drop goes horizontal. If "long sweep 90s" are not available in your locale, two 45s can be substituted, though these are not as quiet. If the plumber reams all pipe sections, which is considered good practice, this will somewhat reduce turbulence noise.
Insulating pipes and housing them in a chase/soffit that has 2 layers of heavy drywall on them will also help contain the sound.
I used Great Stuff for windows and doors (squirt foam in a can). The window and door version doesn't get rigid and thus dampens sound better. We have the main line from the upstairs of our two story home set in the stuff and it's very quiet.
I'd also recommend the Panasonic bath exhaust fan. Much quieter than Braun or even Fantech. We used Panasonic in the bathroom, Fantech in the kitchen, and the quietest Kenmore range hood. The Fantech 6" outside mount fan with muffler is quieter at moving about 4 times as much air as the range hood. We like to stir fry occasionally, so we put both the range hood and the ceiling mount intake for the Fantech unit in our kitchen. We also used a smaller Fantech unit with two intakes in the upstairs bath and it's very quiet, although the quiet is largely because of the 24" plus insulation that's between the actual fan and the bath ceiling.
I'm thankful for the loyal opposition! It's hard to learn much from those who simply agree with you.
Debbie-
I would suggest foaming in the pipe at the traps and bends where the sound is likely to come from.
The spray foam insulation in the house walls and roof will really make the house quiet and increase the perceived (as well as actual) quality just by being quieter. Your husband will be thrilled.
I always throw this in for free when I foam a house. The bathtub can also be done. Throw in a few shots under the stairs and now you get the picture...
Stu
Have you plumber use cast iron in sensitive areas, and wrap the pipes with whatever. I used fibreglass and then some lead sheet that I had laying around. Carpet doesn't sound like a bad idea to me.
I would definitely ask your plumber about using cast iron through the areas where noise might be an issue.
In case you don't know, the modern stuff is generally referred to as "hubless cast iron" -- signifying that it is connected with rubber fittings, instead of the old fashioned cast iron, which was joined at the hub with molten lead and oakum.
If you don't go that route, and choose PVC or ABS instead, packing the joist cavity with insulation will certainly make a difference in sound transmission.
If you are using sprayed foam in the roof and/or exterior walls of the house, I would ask those folks their opinion about spraying foam in the joist cavities with the drain pipe. But I would be cautious, since if you have to have access to those pipes sometime in the future to fix a problem, having them encased in foam could be a big headache. I just don't know.
Don't rely on bare cast iron for quitness. You'll still have to insulate around it.
And since you are going to Batt around the pipe, Pvc will do.
There's a "cellular core" PVC on the market that some one will tell you is quiter, if you install that you still need to insulate it.
To all who replied to me about dampening sound in the pvc drain pipes:
Thanks so much for your comments - I read them out to my husband last night, and he got some ideas, (he's basically the gc, subcontractor and bottlewasher, (he did the electrical, ac and heat), and we've subbed out other parts of the job). Unfortunately, the pvc pipes are already in, so the ideas about cast iron may work for the next house, (ha!), but not this one. But the insulating ideas, and cautions about thinking ahead to repairs, were helpful.
Thanks again.
Debbie