Help with under slab plumbing for new house

[Reach4]

Thanks for the feedback, I did in fact forget the vent take off between shower and wc on bath 2 (first photo.). Got that in there now.

While drain after toilet was not needed (if that is what the combo is), no harm in having it.

 

[wwhitney]

Thanks for the feedback, I did in fact forget the vent take off between shower and wc on bath 2 (first photo.). Got that in there now.

How'd you do the under-slab dry vent take off? 2" wye rolled up 45 degrees above horizontal, then turning the vent back horizontal just below the bottom of the slab, to run to a wall, where you turn up with a LT 90?

Maybe too late now, but an alternative is to wet vent the WC and the bathtub from the lav in Bath 2 like you did in Bath 1. You wouldn't have to change much, just move the kitchen tie in a bit further downstream to make room for moving the toilet tie-in to downstream of the lav.

And just to double check, your Bath 1 lav and Bath 2 shower vent (or lav if it's your only vent) are both 2"?

Cheers, Wayne

 

[Sponsor]

 

[Jeff H Young]

no need having the clean out in the wall you put a 3 x3x2 combi at the lav and continue out the building underground with a 3 inch 90 looking up . so you wind up with a cleanout flush with ground. not so unsightly. btw a 2 way clean out would only serve bath 1

 

[jeffesonm]

How'd you do the under-slab dry vent take off? 2" wye rolled up 45 degrees above horizontal, then turning the vent back horizontal just below the bottom of the slab, to run to a wall, where you turn up with a LT 90?

Maybe too late now, but an alternative is to wet vent the WC and the bathtub from the lav in Bath 2 like you did in Bath 1. You wouldn't have to change much, just move the kitchen tie in a bit further downstream to make room for moving the toilet tie-in to downstream of the lav.

And just to double check, your Bath 1 lav and Bath 2 shower vent (or lav if it's your only vent) are both 2"?

Cheers, Wayne

Yes both vents are 2”.

is this what you were suggesting?

Kitchen sink not shown but it follows parallel and then long sweep 90 up.

 

[wwhitney]

Precisely.

That's a standard UPC wet vent--just one vent, a dry vent for the lav; lav and shower join together first, then toilet comes in last; kitchen comes in after the whole bathroom group.

The only caveat is that some people say that where the lav comes in the combo should be rolled horizontal, so you have a short horizontal wet vent section to the lav fixture drain. Personally I don't see how that performs any better, nor do I see any language in the UPC that requires that. But if you want to try to parse the language yourself, it's here:

https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/9/vents#908.2

Cheers, Wayne

 

[jeffesonm]

In looking at this again, could I skip the parallel 2” drain by adding a vent take off upstream of the shower, and then have the 2” kitchen sink drain enter the 3” upstream of that? Then tie the two vents together above the flood rim of the kitchen sink?

 

[James Henry]

View attachment 67319 In looking at this again, could I skip the parallel 2” drain by adding a vent take off upstream of the shower, and then have the 2” kitchen sink drain enter the 3” upstream of that? Then tie the two vents together above the flood rim of the kitchen sink?

Leave it the way it is.

 

[wwhitney]

In looking at this again, could I skip the parallel 2” drain by adding a vent take off upstream of the shower, and then have the 2” kitchen sink drain enter the 3” upstream of that? Then tie the two vents together above the flood rim of the kitchen sink?

Once the kitchen drain comes in, you can't do any more horizontal wet venting. So if you want to wet vent the WC and the shower via the lav, the kitchen drain has to come in downstream of all the bathroom fixtures.

So, like James says, leave it the way it is. Looks good.

Cheers, Wayne

 

[jeffesonm]

Thanks, will stick with the parallel sink drain.

Got most everything put together, should be able to finish it off in the next day or two, weather permitting.

Going back to the clean outs for a minute...

I had planned to just extend both 3" main lines flush to the edge of the slab so they'd be accessible from outside. The elevation is such that they'd be visible, a few inches off the ground. I was hoping to get away with a few wraps of foam but after speaking with the inspector it sounds like they need to be sleeved just like the main line going outside the house.

Anywhere I can find 5" PVC? Or just sleeve with 6"?

 

[Tuttles Revenge]

you should be able to Sleeve 3" pipe with 4" pipe.

 

[jeffesonm]

Unfortunately, my AHJ feels otherwise so I will be replacing this 4" sleeve with a 6" sleeve.

He also does not like either of the went vent setups, so I will be adding more vents

He also wants the p-trap glued on (I had glued the trap arm into place with a knock out cap)

He is the building and plumbing inspector and I have many inspections to go, so seems best to make the changes requested vs argue about code.

 

[wwhitney]

Sorry you got a micromanager inspector who's exceeding his authority.

Edit: Unless the inspector is also the building official for your jurisdiction, he's not actually the AHJ, just an employee of the AHJ. So you should be able to appeal to his boss, might be worth it for the wet venting (the other things are minor). But as you say, he could make things difficult for you in the future. Or maybe it's important to show him up front he can't make stuff up. I have no idea.

Cheers, Wayne

 

[Reach4]

Anywhere I can find 5" PVC?

https://www.pvcfittingsonline.com/pipe/schedule-40-pvc-pipe.html?size_in_inches=26
https://www.pvcfittingsonline.com/pipe/schedule-80-pvc-pipe.html?size_in_inches=26

Other thoughts:
Well diggers use 5 inch PVC for well casing in many areas.

I don't know how you would connect with somebody who had a couple feet of 5 inch PVC well casing as scrap.

https://www.ferguson.com/product/20...ld-pvc-well-casing-pipe-p40beps20/_/R-3339483

https://www.platt.com/platt-electri...hedule-40/Multiple/5P/product.aspx?zpid=69315 is schedule 40 pvc conduit, which is similar pvc water pipe. 5 inch PVC conduit may be find-able locally.

https://www.menards.com/main/electr...nduit/pvc-conduit/3652650/p-1444427699114.htm is not in Texas.

 

[Tuttles Revenge]

Would be interesting to see the written inspection card and the code behind the corrections..

Sometimes its best / easiest to comply.. Sometimes you need to have a meeting with their boss. Sometimes you find that the inspector you're having issues with when you leave a voicemail to the chief inspector complaining about the inspector is filling in for the chief inspector and you get to have an odd and uncomfortable meeting in their office at 8am..

 

[jeffesonm]

It is unfortunate, but I'd really like this project to proceed in a timely manner so I'm just making the changes requested.

Below is my proposed layout for water lines. First time using pex... my other house was all copper. Still a little skeptical about this plastic tubing but I’ve read enough to know the skepticism is not warranted. Got a crimper on order and have read about not leaving it exposed to UV. Sleeved in pvc where it passes through footing wall and slab. Hot will be insulated.

Water supply will come in from side of house and up to provide cold to bath/kitchen zone. Then back down and over to bath/washer/water heater zone. Hot will come off water heater, feed this zone and then down and back over to other zone. Between the two ‘risers’ I will run the pex down under the slab, in the same trench as drain pipe.

I thought about doing a small manifold for each zone with home runs to the fixtures. I could hide an access panel behind the fridge and another along laundry wall. Probably 3/4 between manifolds and to/from water heater, otherwise everything 1/2. Seems like 3/8 is fine for smaller fixtures but I’d rather just stick with two sizes.

Any benefit running 1” supply from meter? The meter tap is 5/8 (city water) and 1” seemed a little a little overkill for a ~1150 sq ft 2 bed 2 bath, but I could be convinced otherwise. Any other comments, suggestions, tips, etc would be much appreciated.

 

[Jeff H Young]

Ive had some interesting conversations with inspector and gave my opinion more than once never went above his head. sometimes he agreed , or compromised, or got his way

 

[wwhitney]

Between the two ‘risers’ I will run the pex down under the slab, in the same trench as drain pipe.

Does the plumbing code have a separation requirement between the building drain and the water lines?

I thought about doing a small manifold for each zone with home runs to the fixtures.

There's something to be said for a manifold on the hot water side. If hot water draws are intermittent, then the tepid water to empty from a home run 1/2" line is less than a 3/4" trunk plus a 1/2" branch.

Any benefit running 1” supply from meter?

I would say yes. 3/4" PEX is only a little bigger inside than 5/8" copper.

Do you want a hose bibb in the back? Any irrigation? If your lateral is 1", then it would make sense to continue the 1" to either of those.

Cheers, Wayne

 

[Jeff H Young]

Ive never plumbed a house with only a 3/4 service, probebly work fine . size it out. If it meets minimum code go for it. I prefer 1 inch minimum

 

[Reach4]

Got a crimper on order

Had you opted for stainless steel clamps instead of copper rings, one tool could have done the 1/2, 3/4 and 1 inch.

 

[jeffesonm]

Does the plumbing code have a separation requirement between the building drain and the water lines?

There's something to be said for a manifold on the hot water side. If hot water draws are intermittent, then the tepid water to empty from a home run 1/2" line is less than a 3/4" trunk plus a 1/2" branch.

I would say yes. 3/4" PEX is only a little bigger inside than 5/8" copper.

Do you want a hose bibb in the back? Any irrigation? If your lateral is 1", then it would make sense to continue the 1" to either of those.

Cheers, Wayne

The only separation requirements I've been able to find in UPC is 1501.12 but those are alternate water sources for not potable applications. 312 and 314 mention trenches but nothing about separation. Also just to be clear this is the "interior trench" if you will, inside the building perimeter. The exterior sewer and water line trenches are about 15' away from each other.

I google'd around a bit and "multiport tee" is more what I was thinking vs a true manifold with shutoff valves. Basically something that avoids me stringing together a bunch of tee's. The is a real small house so I'm not terribly worried about time for hot water.

No plans for irrigation but was thinking a hose bib under the water heater.

I'm sufficiently convinced to do 1" from the meter. One 100' roll of 1" should get me from meter, to/into house and then feed cold to both zones. Then I can do 3/4 hot back to first zone.

Had you opted for stainless steel clamps instead of copper rings, one tool could have done the 1/2, 3/4 and 1 inch.

Sorry I should have said clamper not crimper... the stainless clamp model is indeed the one I ordered.