Feedback on Drain Design

Hi all,

I've been lurking for months as we planned our renovation, and the framers have our addition to the point where I need to get my rough-ins done. I've worked up the following from what I've read here and my reading of the code. I'd really appreciate any feedback-- it's easy for a beginner like me to get the wrong fitting...

Some background. The house is a 1910 Florida Craftsman that's long suffered at the hand of the unpermitted DIYer. I'm cleaning up issues as fast as I can, but in the meantime we're adding a garage and laundry room. In the laundry, we'll have a sink and washer, so I'm planning to size drains @ 2" for the 4 DFUs. In both sketches below the joists run from top to bottom.



The difficulty lies in tying into the existing drain. Using the most logical (to me) drain design in the addition, I have a 22.5' of horizontal run (shown in "new mudroom" above, longest run is from washer). I have an additional 25' of horizontal run from the edge of the addition through the existing crawlspace to get to the nearest existing drain, a 4" horizontal. (I've looked at going outside and tying to the sewer, but the run is far too long vs. available height).

In addition to the long overall run length, I have a relatively shallow crawlspace: 18.75" from the bottom of the existing joists to the top of the 4" existing drain. To further complicate matters, the new joists are 8.5" lower than the existing joists.

Below is the plan I have worked out (sorry for flipping the layout 180 degrees in the below drawing). I think I have the drops correct (I literally have ZERO extra vertical available with this plan, hence the wye on it's side). I think it's really too much to visualize (go for it if you're a spatial ninja!) so what I most want feedback on are if the fittings I have shown are OK. In particular, the only way this can work is if the 4"-4"-2" wye is on it's side-- is that allowed?

I also need some guidance on where I should put cleanouts. The addition crawlspace with technically be accessible, but it will be a major PITA, so consider it unaccessable.



Many, many thanks in advance for feedback and I promise to pay it forward if/when I learn enough to give good feedback to others.

Matt

quote; that's long suffered at the hand of the unpermitted DIYer.

AND what are YOU, if not an "unpermitted DIYer"? If you had a permit, you would have submitted a drawing to the city and THEY would have either OKed it or told you to revise it until it WAS OK. It appears you have 14" of clearance when you enter the existing crawl space so you probably do NOT have enough elevation for 6.25" of fall. Y's and combos can be installed in any orientation (except upside down, of course).

hj said:

quote; that's long suffered at the hand of the unpermitted DIYer.

AND what are YOU, if not an "unpermitted DIYer"? If you had a permit, you would have submitted a drawing to the city and THEY would have either OKed it or told you to revise it until it WAS OK.

Click to expand...

This project is permitted-- my city allows homeowners to perform work on their own home. My city does not require isometrics so they were not submitted. I'm planning to discuss my plan with the inspector before I plumb it, but I thought I might get some pointers in advance here. If I sounded harsh towards the prior DIYers, it's not so much because it's unpermitted but more because it's completely, completely wrong: galvanized distribution transitions to copper back to galvanized to copper again with dead-end/capped runs, drains supported by piles of unmortared bricks, distribution pipes unsupported at all, just laying in the dirt, etc etc. I can show you photos that would make your head spin.

All of the work I do will be 100% permitted, and I'm just here to try to get the plans as good as I can BEFORE I talk to the inspector which will happen BEFORE I plumb anything.

hj said:

It appears you have 14" of clearance when you enter the existing crawl space so you probably do NOT have enough elevation for 6.25" of fall. Y's and combos can be installed in any orientation (except upside down, of course).

Click to expand...

Thanks for the info on wye orientation. Can I ask why you don't think I have enough clearance? I have 11.75" total clearance between the top of the new wye and the bottom of the new joist. If the wye can be on its side, doesn't that mean I have the full amount of clearance to use for my fall? My plan was to use 6.25" of that clearance for the drop in the 25' run in the existing crawlspace, leaving me 5.5" to use for drop in the new laundry room. This is slightly less than I need so I'll have to bore through the joists from the long wye to the washer to get enough fall.

Thanks again for the help,
Matt