I need an old fashioned slop sink in the garage. I bought the sink, faucet, and other items.
I need to prep for the plumber. I have to tie into the plumbing behind the washing machine. The slop sink will be in the garage on the laundry room wall. That’s 40 inches to the right of the washing machine.
I want to neatly cut out a section of drywall (with a drywall saw), cut any fasteners(with my reciprocating saw) and save that drywall. I’ve cut a bunch of short 1x2’s 7" long, to attach along the edges of the drywall opening for side support.
Those 1x2’s give me something to screw into later when I replace the drywall. It should be roughly 12" wide by 40" long.
I can use some spackling to hide the crack later.
I found a photo that gives me an idea what’s behind my drywall.
Very similar. My hot water tank is on a similar platform, with dryer vent running under it. The door for the hot water closet is in the garage.
Plumbing box is between two studs. Stack to the left. I’m not sure which side my stack is on.
Ok, now the question.
Will the plumber tie in to the washer drain above the trap? Or will he need to tie into the stack?
I’m cutting drywall below the plumbing box and 40 on to the right. The stack may still be hidden behind drywall. Just depends on wheter it’s to the left or right.
I’m hoping it’s an easy tie in above the trap. I’m not sure about code.
Whether we got to get into the stack.
I have the same issue with that dryer vent to the right of the plumbing box. I bet my stack is to the left. Just like the photo. That’s the most logical place to locate it.
That’s why I’m hiring a plumber.
I’m just minimizing the damage to my drywall and making it easy to patch afterwards.
In that picture, I’d WAG the plumber would use the space between the trap and the drain. If he goes above the trap, there’s a chance that when the washer drains it’ll siphon the water out of the sink trap.
What he may even do is go from the sink trap, into the wall and install a Tee (pointed up and down). Run the drain to the spot between the washer trap and the stack, then run a vent up and over and connect it to the stack.
He may even tie into the vent, but then right a pipe from whichever one is lower, to a higher point.
Drains are odd and stacks have to be done in very specific ways. I could be totally wrong in what I said, but I recall reading/hearing something about how a vent can’t have anything above it. Once you tie a drain into the stack things change.
My bigger questions is, as long as you have a plumber coming out, why not just let him do the entire thing? Alternatively, if you can handle opening up drywall, properly stubbing in the drain and patching the dry wall, what’s he doing? If he’s just running the copper, that’s probably easier than the drain.
Plumbers open up walls quickly. At $75 an hour, that’s a good thing.
Leaving an irregular hole that has to be enlarged into a rectangle or square. Then patched, taped, mudded, sanded, mudded again, sanded again, and then painted. Fixing the drywall can cost more than the plumbing work. Unless it’s a DIY.
I’m trying to very carefully remove a section of drywall and put it back afterwards. I’ve done it before getting inside walls for electrical work. It may take a few hours on a Sunday, but the savings in my wallet make it worth it.
JoeyP I think you’re right. I too vaugely recall that two traps can’t be tied together. The trap under the sink has to tie in to the stack separately.
In general, it’s a bad idea to have 2 plumbing fixtures running into the same trap.
Especially bad when one of the sources is a garage ‘slop sink’ – people tend to pour all kinds of things they probably shouldn’t into them. Like washing out paintbrushes and sending paint chips down the drain, or cleaning oil-soaked tools (or even pouring used oil down the drain!). Encourage your plumber to use oversized pipe for this, and install an accessible cleanout.
I agree with JoeyP, I think the plumber will likely connect into that short horizontal section between the trap and the vertical stack. But I’d think he might use a 45º connection pointed toward the stack rather than a T.
Note that you will also need a vent line, coming up from the sink (higher than the sink) and going up to the roof, or connecting to existing vent lines. The most likely place would be to connect into that stack, at about head height above where the drain connects. So you are likely going to need another section of drywall removed there for that purpose.
P.S. Most plumbers hate doing drywall work – it’s not their thing. So their bid often says that it “includes only tearing out drywall & doing the plumbing. You will be left with holes in the drywall, and you have to hire somebody else to replace that.” So if you tell your plumber that you are planning to remove the drywall where he has to work beforehand, and replace it afterwards, he will probably be delighted. And quite willing to stop over some night, look at the job, and show you where he will need access, without charging you extra. Ask him.
P.S. Often, it’s easier (and even cheaper) to replace one whole 4’ x 8’ sheet of drywall than to do 1 or more small patches. Especially when you need one down low for the drain and one up high for the vent.
Just occurred to me. That stack runs through the roof to vent.
I should be able to tell if it’s to the right or left of the washer. Any info before I cut is helpful.
I appreciate the feedback.
Money is tight right now and we had just finished renovations. Now we find out my mom is using a commode chair. Sometimes her clothes get soiled. They require rinising out before going in the machine.
A slop sink is needed to wash out uh, nasty stuff.
Well, no, I don’t mean have him do the drywall. Spend all the time you want ripping that out beforehand and you’ll as much time as you want to replace it. I mean, why are you drying to screw around with the drain to have (I assume) run the copper. Just let him do both.
Drains are complicated, have a lot of code requirements and aren’t always that easy to deal with since that PVC doesn’t typically bend, flex or have enough ‘slack’ to shove over one way or the other. That is trying to get any type of fitting into an existing run of PVC is a PITA. However, plumbers do it day in and day out. They know how, they have tricks and they have tools.
Having said that, I was curious why, if you have the ability to this, why not just do the entire job?
When I said that he may use a T, I mean that he’d be using a T to do this:
OP, you should keep in mind that even the shape of the connectors can come down to State and local code. For example there’s multiple types of connectors that you could use to tie into an existing run. They all look kind the same, but they’re different shapes (wye or tee for example) and used in certain applications.
Like t-bonham said, see if the plumber will come out ahead of time and tell you where to open up the wall. Letting him spend the extra hour there to do the drain will be preferable to a life time of gurgling noises or sinks backing up or sewer gas in the house.
If all you want to know is where to cut the drywall, I don’t think there’s any good way to tell you that. You really have to let the plumber tell you what he wants. Even if you gave us a picture of your actual house/wall with x-ray vision so we knew what was behind the drywall, we’d still be guessing at what the plumber is going to do. There’s not much point in cutting out the drywall where you assume he’s going to work, just to find out you wasted all that time and money because he’s going to do something you didn’t expect.
My suggestion: you’re spending too much time overthinking this. Let him bash in the drywall with a hammer, where he needs his holes to be, then square it off with a keyhole saw or razor blade and patch it up. Even better, just remove the rest of the sheet so you can just put up a brand new one, no cutting required (in a perfect world). You can pick up drywall at any Big Box hardware store, even 4x4 pieces so they’re not huge and unwieldy.
Because this involves code work (especially since it’s a drain), I might be hesitant to just let a handyman do the entire job. However, ask the plumber if he has a drywall guy. It’s entirely possibly he’s got one or two people he calls to come in after him to patch up walls. There’s no harm in asking. Who knows, it might just cost an extra $50 or $100 and then you’re not spending a day sawing/taping/mudding/sanding/priming drywall. And if it’s too much, you just continue on with your current plan to do it yourself, he likely doesn’t care one way or the other.
PS, if you’re having a permit pulled for this (I assume not, but if you are), the final inspection will have to be done before you close up the wall.
When I worked in a local hardware store/lumber yard, we threw away broken drywall all the time. We’d also send broken chunks home with anyone that asked, because that meant less to throw in the giant, roll-on dumpster that costs $$$ for them to empty. I’m sure if you asked, you may be able to get the drywall at little or no coast at all. I’m not sure if the “big box” stores would do this, though.
At $75 an hour, that’s a good thing.