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rebeccah1_gw

Need to redesign bathroom DWV

rebeccah1
17 years ago

Hi,

I've got an old California bungalow that someone added a bathroom to some 7-10 years ago (two owners ago). They didn't do it right, and I'm trying to figure out how to fix it. California uses UPC as its model plumbing code.

I don't know where's a good place to post photos for you to see what I have now, but I've posted them on Taunton's Breaktime forum (you need to register to even read the posts, unfortunately, but it is free and I haven't gotten any spam and I've been there for several years):

http://forums.taunton.com/tp-breaktime/messages?msg=85574.7

And I've posted sketches of a couple of approaches I'm considering:

http://forums.taunton.com/tp-breaktime/messages?msg=85574.21

Anyway, here are my current questions:

1. How long can a trap arm be before the vent takes off? I understand the connection from the trap arm to the vent must be higher than the weir, and that there can be no more than one pipe diameter of drop (which basically means the same thing). If horizontal pipes are supposed to slope a minimum of 1/4" per foot, then I guess for a 2" diameter pipe, that would mean a maximum of 8'? Seems awfully long, but I don't see any references to maximum length, only minimum length to the vent (which I think was 2 pipe diameters).

2. Can the drain continue horizontally after the vent comes off (i.e., T fitting with the top of the T on the bottom being the trap arm and drain, and the base of the T on top being the vent)?

3. If the WC has a combo fitting connecting to a horizontal drain line below it, can the vent for the WC come off the high side of the drain, or does it have to come off the low side?

4. How big are the holes allowed in 2x4 studs? What about top plates?

5. Is it OK (though ugly) to run the vents on the outside of the building? This is SF Bay area and we get about 3 frost days a year.

The layout of the fixtures is within about a 5' x 6' room on an outside corner of the house, door to the room is on the inside corner. WC is in the corner on the left, lav is in the outside corner, and shower stall is in the corner on the right. It's hard to draw in 3D when the fixtures are on two walls, so in the drawings at Breaktime I left out the lav, which is of course higher up as well as out of plane. It might be easier for it to get its own vent (it almost has one now), I'll ask about it once I have some more of the basic concepts clear.

If I need to post the pictures somewhere that doesn't require registration, let me know. Breaktime is a great forum, though.

Thanks for any suggestions!

Rebeccah

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