Building a new house and my upstairs bathroom is directly over the
dining room. I'm a little concerned about the noise of a flushing
toilet (and a draining pipe) invading the quiet of the dining room. I
am assumming that most of the noise of a draining pipe comes from when
the water changes from horizontal to vertical (between floors) and
splashes at the bottom. (Is this true?) The toilet is near the wall
separating the dining room and kitchen. I could bring it down this
wall, or I could divert the toilet waste parallel to this wall and
bring the water down the wall separating the panty and the dining room.
This pantry wall is ideal because the presence of a built-in china
cabinet will certainly reduce the amount of noise coming from the pipe.
However to get to this wall I have to cut through six or seven 2x
10"s on 16" center (the pipe would be running perpendicular to the
floor joists). Cutting 4" holes on 2 x 10's just doesn't sound like a
Also, am I fooling myself? Is running the horizontal pipe in the
ceiling for an extra 8' to get to the pantry wall a good idea versus
going directly to the closest wall and dropping it there? I am
looking for suggestions.
Here are the ones that I have heard:
1. Replace waste pipe with cast iron - cast iron is quieter - don't
like that idea - really like the ease of PVC - do not like the weight
of cast iron. However, if I do put in cast iron, how much? From the
closet bend to the crawl space?
2. I have also been told that I could add steel plates to the 2x10's
and stiffen up the joists which would allow me to drill the holes with
Are there any other good ways to insulate and negate the sound? All
You're right to be concerned about the noise.
I hear that this material is *very* effective with PVC.
I, too, vote for cast iron, all the way down.
Besides the rush of water being audible with PVC, there
is a follow-on of a tortuous "drip...drip...drip"
as the pipe completely empties. In a quiet room this
can be disconcerting, to say the least.
Whichever DWV material you choose, see if the 3" size
will be permitted (there's no sound reason not to use it).
This could result in greatly reduced weakening of beams.
Also do some research on the noise generated by toilets
available today. Not just the flush, but the refill as well.
Lets get real here. You were actually considering cutting almost 1/2 way
though 6-7 joists just to avoid some sound. You will have a lot bigger
problems if you do that.
Not only will you lose much of the structure you also will have a horizontal
run susceptible to blockage. Just dump it down the wall. Fill the cavity,
around the pipe, with foam if the sound is going to bother you that much.
Let's be realistic. You are building a house that costs 100's of thousands
of dollars, you are converned about the plumbing noise, yet you are not
willing to put in an extra hour or two of work to solve the problem? Stop
being a lazy and cheap SOB and do the job right. You have to live with
your decision for the next how many years?
Even the one where I called you a lazy and cheap SOB?
The house should be designed from the ground up to allow a chase for the
drain lines. If you wanted the line to run where it will cross a bunch of
joists, the joists should have been built to accommodate this run. To change
it and cut the strength out of half of the joist in a room is inviting
serious problems. Build it as it was designed. Have a truck mounted foam
sprayer come in and encapsulate the run in foam, it will help muffle some of
the sound. I am sure you will find other areas to foam up while he is there.
On 17 Apr 2006 11:35:29 -0700, firstname.lastname@example.org wrote:
DONT cut through all those joists. Sound insulation, installed
PROPERLY, works very effectively.
And remember, when cutting a joist do NOT cut the bottom or top of the
joist. Cut out the center only. You loose hardly any strength when
cutting out the center of the joist. If you cut out the bottom or top
of the joist you almost destroy that joist entirely.
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