How to Install a Basement Bathroom

Richard Trethewey shows how to rough-in the drainpipes for a basement bathroom. (See below for steps.)

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Steps for How to Install a Basement Bathroom:
1. Lay out the 2×4 bottom wall plates to establish the perimeter of the bathroom walls.
2. Measure off the wall plates to locate the center of the shower drain and toilet flange.
3. Dig a trench extending from the existing drainpipe over to the new locations of the shower drain and toilet flange.
4. Use a right-angle grinder fitted with a diamond-impregnated cutting wheel to cut through the old cast-iron drainpipe.
5. Attach a flexible no-hub mechanical coupling onto the end of the just-cut drainpipe. Tighten hose clamp onto the cast-iron pipe with a torque wrench.
6. Cut and glue together 3-inch-diameter PVC pipes and fittings to form the drainpipe assembly that connects the old cast-iron pipe to the new shower and toilet drain.
7. Slip the end of the PVC drainpipe assembly into the mechanical coupling attached to the old cast-iron pipe. Tighten the hose clamp to secure the PVC pipe.
8. Next, run 2-inch-diameter PVC pipe from the drainpipe assembly over to the shower and vanity sink.
9. Install traps for each fixture, and be sure the pipes slope 1/8 inch per foot to drain properly.
10. Drive a 1/2-inch-diameter steel-reinforcing bar down into the soil beside each trap. Then, use duct tape to secure the bars to the traps.
11. Have the rough piping inspected before pouring the concrete floor.
12. Cover the open end of the toilet pipe with a foam cap. Wrap plastic around the shower-drain pipe.
13. Have the concrete contractor pour a new floor around the piping.

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Lucky Joestar says:

They’re putting their master suite in the basement? I thought only the adult children had their rooms down there.

kris says:

3inch pipe for a toilet?!! No thanks! I’ll stick to our 100mm pipe in the UK thanks, someone flushes too much toilet paper and you’re buggered

Michael Castillo says:

That Fernco band was a bad choice.

Rob Bravo says:

individual vent is much better

Al Delgado says:

Why arent you using abs black pipe?

Inachu Ikimasho says:

If you buy one of those tiny toilets then I hope you suffer pain. all toilets today are built for people who are just 5 feet tall.

Mark Bidwell says:

Like how you rolled up the branch lines,so shower ,and vanity drop into toilet mainline

bkdreamer says:

Should have used cast iron reducer. That rubber reducer is garbage.

Barrett Eggebraaten says:

Would not meet MN state plumbing code. Want code is being used?
I also would have used a 4×3 90 for the water closet. Aka stool. And just putting some crumpled up Polly around the shower drain is not very professional looking

Alleriea Alleriea says:

i dont what code you work with but you have no backwater valve to protect the bathroom in the basement.

Jayson Edwards says:

You can’t wet vent 2 fixtures off of a water closet And code calls for a minimum 2″ vent for a toilet/water closet You’re event has to be with thin 5′ of your fixture he is way off this would not pass inspection with city inspector. And 3″ pipe is a minimum quarter per foot fall/grade/pitch and 2″ as well 4″ pipe you can run it at a 1/8 per foot but 2 and 3″ must be A 1/4 per foot fall

Evnflw1 says:

When I was a plumber in Mass a Fernco was not code. 4 band mission clamp underground only.


you guys are rockin it

Random Stuff In Oregon says:

I kind of like the sound of gurgling that comes from unventeted pipes.

Cristian Munoz says:

Funny how an ad pops up on the only time when they mess up by turning the cast iron fitting

MOPARGuy says:

Love the comments from all the YouTube licensed plumbers.

Thomas Broking says:

Very nice. I like a little more off the wall, if there is a change and tile added. Plus a half or an inch i like for cleaning. I ask what the customers prefer..

Daniel Gallagher says:

Remove cast from bell, install pvc ferrell, pack pour lead right into that bell, no band not disturbing a thing @ Philadelphia plumbers best tradesman in world

Mrdead Inmypocket says:

Watch @ 05:01 when he’s tightening the clamp, the cast iron pipe swivels. That means the lead seal is bad. It’s going to leak.

Doctor Ambulance says:

carbon fiber strips on the walls… yeah those dont’ work lol

Scott Miller says:

He uses a face shield (which is good) and then a grinder with the guard removed and no gloves! How does think the lavatory drain pipe is going to vent when he just said that it has to have a p- trap on it? – he said that every pipe will have to have a p-trap! Is it going to suck the water out of the lavatory p- trap to vent the rest of the system, and then not have the necessary water in it to prevent sewer gas?

seededsoul says:

4:14 Agh don’t cut your thumb!!

Bret .Maverick says:

They have 2 different plumbers and it’s going to be inspected the next day. So is it everything okay with the YouTube experts? Or are people going to find some reason to complain any way?

Michael Shilshtut says:

I don’t really care about this video much but I just love reading comments. Such a fun time. God bless YouTube, God bless American inventors.

Jézeďák Laďa says:

Sorry, but you in USA has got a shit pipes, connecting is for glue, we in Morava has got a PVC HT pipes, we hasn’t got a glue – why? We have got a sealing in the pipes.

psykofaty says:

Is there no worry of igniting sewer gases from using that grinder?

john james says:

looks like they had the basement de-watered at one time…

Tony lee says:

@ 4:10 Using Your Finger For A Sawzall Guide Is Retarded

Dfk429S9fo3 says:

Why wouldn’t you just go 4″ to the toilet?

Lee Olaeta says:

Really? Wet vent? Let’s start with the 3 inch line. Anytime you make a 90 degree in a waste line you must install a clean out. This bathroom has No 3 inch clean in side for the main line.
2nd once you make that 90 if you are going to wet vent the toilet it must be tied into that pipe between the toilet and that 90 or it’s no longer a wet vent. It’s a “I hope it Works Vent” Those aren’t code legal.
3rd. Did you notice how at the 3×2 Y the 2 inch pipe was rolled up at 45° Up from the 3 inch pipe. At the next 2 inch Y you must either roll this fitting up or roll it up an stick a street 45 into the Y to bring it back to flat or minimum of an 1/8 of an inch fall. If the shower is more than 3 feet from that Y. It must have a vent also. So, I’m pretty sure none of this job would pass inspection in California. Most importantly is that if I had a plumber doing this job working for me. I would tear it out. “FAILED THE BOSS TEST
The mechanical fitting that they used wasn’t code legal either.
Did they snake this line to clean it before tieing to it. After snaking it. Did they send a camera down it to make sure it’s in good shape,
Once you get 2 feet away from the house it is no longer cast iron. It’s either terracotta or clay. Which more than likely has failed at every 80 year old fitting. Use the old 4 inch line under the foundation as a chase. Stick 3 inch pipe through the 4 inch pipe. Tie it on to the 4 inch outside of the house.
Now everything in side the foundation is New.
This Old Junky House.

toilet brush says:

just two old guys flexing their professional measuring tapes

MACK D says:

4:16 I thought he was going to say, “it’s always good practice to keep your thumb well away from a moving blade.”

Marcus N says:

You slick fuckers broke that cast iron pipe at 5:06 in the video. You guys are not ready for concrete. Thumb down for even posting this

Jack Manor says:

these comments are simply classic. as soon as he measured the offset at 12.5″ and not 13″, i knew this was gonna be loaded with goodies. nobody here let me down either. hahahaha.

Dosadoodle says:

No ear plugs with the grinder?

Stanley Keith says:

The old cast iron pipe looks like it might leak, maybe you caused the seal that has lead in it to leak. If this is cemented over could it leak under the slab. How can you tell if you did not disturb it. Look at 3:17/8:00, and at 5:00/8:00.

Copykon's Music says:

This is the easiest install of all time being that there was already a bathroom there.

Elena Marian says:


Joseph Serrano says:

Why didn’t he prime the pvc and pvc fittings before applying the clear cement?

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