Main sewer line with more than 1/4 pitch...

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Jeff H Young

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There are a lot of drawings I was refering to post 8 and 13 drawings but didnt mention of cource trap arm lenght does apply . and some drawings were not proper and could be confused. again , trap arm lenth and fall does matter on trap arms
 

Tuttles Revenge

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In Seattle only, I was verbally told by one inspector that the maximum grade for Horizontal wet venting is understood to be 1/4/ft. But its not written anywhere.
 

Niloc75

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Yes

A 2" Cleanout tee is best above the san tee for the lav. It can be installed behind or even flush with the sheetrock and accessible with a chrome cleanout cover or a plastic access panel.

No. Since you won't have access to those parts, they need to be glued.

We call this a Blind Set. It sucks. First things first. Set the tub in the alcove and get it perfectly level across the back and sides and scribe a line on your studs. Determine whether you need to place the tub in a bed/pads of mortar or just use a ledger board. How we do set up the blind set, is to build the waste and overflow of the tub first. The tub shoe meets the overflow at a san tee at the wall usually. So your trap needs to be set to receive that waste tee. You can measure the center of the tub drain from the corner of the actual tub, not the given dimensions. Get the trap in place but don't glue it together. Then guess the difference in height from the trap to the tub tee. Dry fit that into the trap and set your glued together waste and overflow on top with the tub out, then install your tub to your scribe line or on the ledger. See if the waste and overflow match up to your tub, use the rubber gasket on the shoe too, they need to be part of the measurement... If it does, you just won the lottery. If not, adjust what you need until they do. Once you have it all lined up and perfect mark your fittings to the pipe with a marker and glue it up. But act fast. Set the tub and install your screwed in drain and overflow pieces to double check.. if that checks out, let that assembly cure for a bit. Now you can pull the tub and place mortar if needed and re set the tub with little effort.
thanks again--
 

Jeff H Young

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In Seattle only, I was verbally told by one inspector that the maximum grade for Horizontal wet venting is understood to be 1/4/ft. But its not written anywhere.
I dont know cant rock the boat too much but that would mean the maximum fall and the minimum are exactly the same wet venting a w/c with a branch horizontaly for a lav I dont see how if its falling at 3/8 inch per foot would hurt anything at all but he is the boss. A lot of guys really think it looks kinda sloppy screaming down hill I kind of agree but I think its mostly cosmetic looks.
 

Niloc75

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Hey there. Need to check on one more thing... For the sink/toilet wet vent and the tub vent, I've assumed that it needs to be rolled to a 45 degree pitch above the toilet drain. But do I need to maintain that 45 degree pitch all the way to the wall, before it goes vertical? Or is it ok to convert to 1/4 per foot pitch until it goes vertical (like below)? Also, does the tub drain need to enter toilet drain from 45 degrees above as well?

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wwhitney

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I didn't review the earlier parts of the thread.

As regards that diagram, it is out of date. In that if the vent is to be a dry vent, then the 45 degree angle above level has to be maintained until 6" above the flood rim, which the diagram violates. And if the vent is a wet vent, i.e. the lav drain, there is no need for a 45 degree elevation, and it would be more common for the combo to be flat (2% slope on both inlets). Actually it would be more common to use a 45 and wye, rather than a 90 and a combo.

Cheers, Wayne
 

Niloc75

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Thanks Wayne. What's your take on the tub vent? Does it need it's own vent, or can it share the wet vent with the toilet and sink? There's been some disagreement on this..

Also, I'm dealing with soft, easily compacted dirt with some clay (and a lot of it). Would you still buy a bunch of sand to surround these drains and sewer? Is it necessary to put gravel/etc on top of sand or dirt before adding concrete?

I'm in Seattle, fyi
 
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Tuttles Revenge

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Back in Post #13 you drew a horizontal wet vented system where the 2" drain of the sink would vent the toilet and the tub. All of those branches need to be Horizontal, and since you're in KingCo/Seattle the unwritten rule is that the minimum and maximum grade for a Horizontal Wet Vented system is 1/4" per foot.
 

Niloc75

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Thanks. I've been getting conflicting info on this. I was told specifically, in another forum, that the wet vent (and all dry vents) needs to "maintain min. 45 degree angle or go vertical". I was also told that the tub drain should connect from 45 degrees above. Sounds like this was not correct.
 

Tuttles Revenge

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Definitely Not correct. Lots of folks don't understand the principle of horizontal wet venting. Also Washington state has ammendments to the UPC that differ from other jurisdictions and Seattle/King Co have their rules for it too.

I should have linked to this from the get go...

 

Niloc75

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1/4 inch slope and one wet vent for all 3 makes this job a lot less complicated. Should've just stuck with Tuttle and company from the get-go. Thanks guys
 
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