Hi, I’m new to the forum and had a few questions. I’m planning a laundry room addition that will have a sink and washer / dryer. I’ve already dug up my backyard where I’m going to tie into the waste line. I think it’s probably 6” maybe 4” diameter. I’ll measure again when I get home, I’ve already dug down to it. My question is at what point is the waste line “resized” down to the 2” that will be in the laundry room wall? Also should I be concered about the waste line and cold water line coming into the foundation footing and then going straight up into the wall? I plan on either wrapping or using a sleeve on the pipes to protect them from the concrete. The hot water is coming through the ceiling from the house.

Link to drawing:

[ibb.co]



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Thank you for adding my drawing! Seriously thank you.

codes vary... mine says minimum size drain pipe thru foundation wall is 4 inch.
i doubt yours is the same ??

Thank you for the reply. I'm planning on branching off the main waste line in the yard over to the new laundry room using 4 inch pipe but once that pipe goes into the foundation and up into the wall is that the point it gets reduced down with a fitting to a two inch diameter pipe? The only plumbing going to it is the laundry room sink and washing machine. I hope my question makes since. I was concerned that a 4 inch pipe was to wide to go up into the 2x4 wall cavity. However it's probably going to be concealed under the sink cabinet so It won't be visible.

put a 4 inch Y and 45 just outside the foundation as a cleanout.
then when you go thru the wall you can reduce the inch to 2 inch right away.
something like this... but face the Y up with a 45 in it to bring the branch to vertical..

Or you could use a fitting that allows you to snake both directions but be cautious when snaking under your slab. Use a qualified plumber that also snakes drains. FWIW.

Thank you for the responses.



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So once the 4 inch pipe goes into the foundation then I can curve it up using 90 degree fitting and as it comes up out of the foundation into the laundry room then I can use a fitting to reduce it to 2 inches? Or can the 90 fitting be what reduces it? I'm not sure if they even make that. Sorry if I'm overthinking this.
Also I'm thinking I want to use a fitting for the cleanout that goes both ways in case I need to snake either direction.

You can use a long sweep 90 or 45 and a street 45. Two combo s put together would make a 2 way clean out. what are you doing for the vent? [www.bing.com]



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The vent is just going to be a standard vent pipe in the wall that goes up and out the roof.

I just realized something. Since my hot water is coming from the hot water heater in the house utility closet over to the laundry room through the ceiling should I just go ahead and have the cold water come over to the laundry room from the utility closet in the house the same way? My current plan was to just tie into the water line in the yard that goes to the backyard water hose spigot and branch off over to the new laundry room but I’m concerned that the new waste line and cold water going to the laundry room will be to close to each other and not not pass code. I remember reading there is a minimum distance when waste and potable lines run parallel.

Edit: After doing some googling on IPCodes I think my best bet is to have the cold water come from the house just like the hot through the ceiling over to the laundry room. I just don’t think I have enough room in my small backyard to have the required code distances between the waste line and potable cold water line coming over to the laundry room site.



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