Converting utility sink to standpipe

theBigSee · Nov 25, 2009

I have a utility sink with a 1.5" trap going into the wall. Right below it (and about 6" above the floor) is a 1.5" cleanout. All the drain lines are cast iron.

Before I start tearing out drywall, I wanted to know if there is going to be a 2" line right under that 1.5" cleanout, or if it opens up from 1.5" to 2" under the slab foundation? I don't want to jackhammer out the floor or tear apart the plate to tie my standpipe into 2", and I don't want to tear open the wall if there's no 2" above the plate to tie into either.

Any insight would be appreciated!

FloridaOrange · Nov 25, 2009

Sounds like it might be 1-1/2" but there's no way to tell 100% without opening the wall.

Sponsor · 2022-01-29T12:20:58-0800

NHmaster · Nov 25, 2009

It's probably 2" under the slab, most older codes would not allow anything smaller. 1 1/2" is not large enough for a washer stand pipe

theBigSee · Nov 25, 2009

I figured it's probably 2" under the slab, thanks for the input. I won't put a standpipe on the 1.5", I don't need any more flooding problems!

FloridaOrange · Nov 25, 2009

Do you have rrom for the sink and the washing machine? Code allows dumping into a laundry sink.

theBigSee · Nov 25, 2009

FloridaOrange said:
Do you have rrom for the sink and the washing machine? Code allows dumping into a laundry sink.

Yes, that's what it currently does. The washing machine is right next to the utility sink and empties into it. I was hoping to eliminate the utility sink because it has overflowed a few times due to things falling in and blocking the drain (t-shirts and such). Also, it would free up some valuable space in the kitchen.

But if the 2" is under the plate, that means jackhammering and ripping up tile and even then I don't know if it will be 2"! I'll have to put this project on the back burner I think . . .

FloridaOrange · Nov 25, 2009

In Florida, used to be that 2" was minimum under slab. The 2" carried through the slab and then transitioned down to 1-1/2" at sinks.

Open the wall up, drywall is pretty easy to replace.

theBigSee · Nov 25, 2009

jakeru said:
FYI - My old clothes washer standpipe and drainline (Cast iron and galvanized steel) were both 1-1/2", and I have a strong hunch were code compliant back in the 1950's when the house was built. My clothes washer drainline remained 1-1/2" going down into the crawlspace, and over a few feet horizontally until it transitioned to 2" wye, which was also fed by the kitchen sink.

But, the UPC code does allows a 1-1/2" cleanout to service a 2" drainline, so I suppose a 2" drainline could be possible in your case as well. HTH!

That's both bad and good news for me -- my house was built in '56 and the 1-1/2" might stretch a ways then. However, the news about 1-1/2" cleanout on a 2" drain is encouraging! I guess I'll just have to cut through the drywall a bit and hope it's 2" on the other side.

Thanks for all the help!

Gary Swart · Nov 25, 2009

Often folks think of a jack hammer as the ones used on major demo jobs, but a rotary hammer-drill will break out small areas of concrete quite easily. Tool outlets like Harbor Freight and Grizzly Industrial sell them for about $80, and of course renting is another option. I use mine only occasionally, but when I want to do any kind of concrete work like breaking or drilling, it's worth the price.

Nukeman · Nov 25, 2009

A diamond blade in your circular saw does the job too. It makes a lot of dust, though (but a jackhammer does too). I picked up a blade for about $16. Score where you want to remove with the blade. Then a couple whacks with a sledge will break the section free.

Dlarrivee · Nov 25, 2009

nukeman said:
A diamond blade in your circular saw does the job too. It makes a lot of dust, though (but a jackhammer does too). I picked up a blade for about $16. Score where you want to remove with the blade. Then a couple whacks with a sledge will break the section free.

I figured that would be dusty, but I'd like to know how bad it is exactly.

I wear a respirator daily anyways, and have a full face respirator as well, but I'm wondering if simply strapping a vacuum hose to the saw while I cut would help with the dust in the room?

Doherty Plumbing · Nov 25, 2009

dlarrivee said:
I figured that would be dusty, but I'd like to know how bad it is exactly.

I wear a respirator daily anyways, and have a full face respirator as well, but I'm wondering if simply strapping a vacuum hose to the saw while I cut would help with the dust in the room?

It's VERY dusty. IE you're gonna want to somehow seal off that room from the rest of the house. And hopefully it's got a window!!!!

Ever cut drywall with a circ saw? It's kinda like that

Dlarrivee · Nov 25, 2009

Doherty Plumbing said:
It's VERY dusty. IE you're gonna want to somehow seal off that room from the rest of the house. And hopefully it's got a window!!!!

Ever cut drywall with a circ saw? It's kinda like that

To be honest, I don't even own a circular saw at the moment... I've got a table saw, and prefer the precision of it, but you obviously can't cut the floor with a table saw.

I should setup a little tent, and a fan to create negative air pressure inside the tent...

Nukeman · Nov 25, 2009

Plan on everything in the room and yourself becoming totally white from the dust in no time flat. It will spread through every little crack if you don't seal the room off.

I got the blade at HD. At the tool isle, they had Bosche blades that were about $35-$40. But, I remembered that they also had some diamond blades over by the rebar. At this store, they had Husky or DeWalt brand blade at $16.

A shop vac would help to keep the dust down. In the Shower section on here, GoldMaple has a good thread and talks about using the diamond blade for cutting the slab. You should check it out. You have to take breaks between cuts. This lets the blade cool and also gives you a chance to clean off your goggles so you can see what you're doing.

Frenchie · Nov 25, 2009

Concrete dust is pretty bad for the bearings in your saw, too.

I don't anyone that makes a vacuum hood for saws, bur Dustless makes one for grinders:

http://www.dustlesstechnologies.com/cutbuddie.htm

I've made something similar, out of cardboard & duct tape & a regular grinder guard & the crevice tool off my shopvac. It works surprisingly well. Helps to have a long hose on the vac, so you can put the vac outside - or a spare hose, run from from the vac's exhaust port, out the window.

Thinking, you might be able to do something like that on a saw. If you can find an old PC sawboss*, they have an dust port you can fit a shopvac to, I do this all the time, cutting wood (see uploaded pic, below). You'd just need to tape some carboard over the side.

...Or, you could just rent a wetsaw.

(* I wouldn't use a new 150$ saw to cut concrete, kills the bearings. Also, my newer Sawboss has a different dust port - shorter, with a tighter sweep - and in-between shopvac hose sizes. The older ones fit 1-1/4" hose, snug & perfect)

FloridaOrange · Nov 25, 2009

dlarrivee said:
To be honest, I don't even own a circular saw at the moment... I've got a table saw, and prefer the precision of it, but you obviously can't cut the floor with a table saw.

I should setup a little tent, and a fan to create negative air pressure inside the tent...

It's very dusty. My brother sealed off the room we trenched with a fan blowing out of the front of his house. That was 4 months ago and I can still see concrete dust in the crevices of the stucco on the front of his house.

Dlarrivee · Nov 25, 2009

Is it possible to find a wet saw that isn't one of those ones that looks like a lawnmower?

Terry · Nov 25, 2009

The easiest method, is calling a contractor with a wet saw.
The one I use, he runs the wet saw, and hands me the wet vac to suck up the water and slurry.

He carries several types of wet saws in his van, for different situations.

I would rather be cleaning up water then dust.
When you are done with the water, just dump the bucket outside.

With dust, it's everywhere. Including your lungs.

It makes a cleaner cut, that's easier to pour concrete to.
And it doesn't fragment the slab.

Dlarrivee · Nov 25, 2009

Terry said:
The easiest method, is calling a contractor with a wet saw.
The one I use, he runs the wet saw, and hands me the wet vac to suck up the water and slurry.

He carries several types of wet saws in his van, for different situations.

I would rather be cleaning up water then dust.
When you are done with the water, just dump the bucket outside.

With dust, it's everywhere. Including your lungs.

It makes a cleaner cut, that's easier to pour concrete to.
And it doesn't fragment the slab.

Wet is obviously best.

hj · Nov 27, 2009

drain

WE cannot tell what YOUR plumber did when he installed it, but here, and everywhere I have been the line in the wall, since it is cast iron, would be 2", regardless of the sink or cleanout thread sizes. IF it is No-Hub cast iron, you could remove the tee and the pipe between it and the cleanout, then insert a 2" tee, with a slightly shorter piece of pipe, the the "P" trap and riser inside, or outside, the wall.

Converting utility sink to standpipe

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