I’m in the early stages of planning an above-the-garage addition for a master bedroom suite. The current preferred floor plan would put the shower drain approx. 45 ft (laterally) from the existing main drain line on the second floor.
The main drain runs down thru the 1st floor wall to the main sewer line in the basement floor.
Is 45 ft. to far? (I have not talked to builders or plumbers yet, just trying to get a feel for viable floor plans.)
One option is to run the pipe 30 ft. to an existing first floor wall, then drop to the basement ceiling and run the remaining 15 feet before dropping again to the basement floor. Would that help?
I hate the idea of excavating a new sewer line tie-in through my garage floor!
Thanks.
Replies
You have to slope it 1/4" per foot. If you have enough vertical space to do that, you're in business. If not, you'll have to make space somewhere.
thats a 1/4 inch per 10 ft .
Most building codes aren't published online, but http://www.taunton.com/finehomebuilding/pages/h00015.asp (page down and click on Inadequate Drain Slope) cites the IPC and the UPC, both specifying 1/4" per foot for the pipe sizes a shower drain would use. The flattest slope they allow, only for 8" or larger pipes, is 1/16" per foot, which is still a lot steeper than 1/4" in 10 feet.
There are reasons behind all this. If you slope the pipe much more than 1/4" per foot, the liquids run around the solids, and leave them stranded high and dry. Much less, and everything sits where it is. The goal is to have the liquids keep the solids moving along.
-- J.S.
Thanks for the update. We are still using the sbc , and I think what I stated is true with it. I will check to make sure however and get back to you. I can see that his distance would run out of floor with the meausement you gave . He will not be under an inspection either. I dont want to take any thing away from what you said , but 1/4 on 10 ft has worked for years where I live which wouldnt get him in trouble with his floor . I would however run a drain steeper than I quoted if he had the height., for that long a run. We are faced every day with making a remodleing project work with out pricing our selves out of business. Ill bet the house he has now doesnt stand up to that fall. I shouldnt question a building code , but this sounds like California. To comply with what you said he would need to put in a pump, or pick up the main sewer line out side. How many people do you think will do that with out an inspection ? Even a plumber will not get an inspection on his job , its remoldeling. At least he wouldnt here. So are we to think that all plumbers would do this ? Ill let the jury here decide.
Tim Mooney
No, not all plumbers slope their lines correctly, just the good ones. A 1/4 inch per foot is good. 1/8 inch per foot is allowed in many areas. Larger pipes can have slighter slopes (like a 1/8 inch per foot) and work fine. My code requires at least 1/8 inch per foot but not more than 1/2 inch per foot.
I would NOT slope a 1/4 inch per 10 feet over any significant run. It will work fine for 5 or 10 feet because there isn't enough time/distance for the solids and liquids to separate.
Unfortunately, in these long runs, it is harder to get the height you need (6 inches in this case) much less the height you want (12 inches in this case). But in these long runs is exactly when you most need to do it right.David Thomas Overlooking Cook Inlet in Kenai, Alaska
You will also have to vent within 6' of your shower (check local codes to verify this distance).