Good evening,

My question is two-fold:

First, for a basement bathroom, can someone please give me an education on what the plumbing consists of from the drain of the shower/toilet/sink to the sewer line?

I would like to be armed with information before I tear into a current project I have in mind.

Second, the reason for my asking for an education. My wife and I live in a house built in 1928. The basement is garden level, and use to only consist of a 'mechanical room' where the boiler was placed for heating. The remainder of the basement used to be a crawlspace and was dug-out in the 50's to make more room; bedroom, game room and a bathroom.
The floor drain in the original portion of the basement is slow, and my wife had a plumber come out at one point to remedy the situation. He said (pardon my lack of proper terminology) that the drain pan was clogged up and needed to be replaced. This drain is a floor drain in the mechanical room; the washer drains into the line adjacent to the floor drain, and if too much water flows down the drain, it backs up into the floor drain. How difficult is it for me to tear out the concrete, repair/replace the drain/floor?

Second question continued; the bathroom that was added to the basement is immediately next to the old 'mechanical room'. The PO poured a 4" slab on top of his first slab, to run his sewer lines for the toilet and shower. My wife and I would like to re-organize this bathroom, moving things around and expanding it. I would like to knock the raised slab out, and put the drain for the toilet and shower at the same grade, but I fear that it is easier said than done. Did the PO put the bathroom on the raised slab for a reason? If I knock out the raised slab and try to put the drains at the basement level, will they drain properly?

Apologies for all the questions, but I am trying to be proactive and educated before I blindly break up the concrete in the floor.

Regards,
Chris

Good morning Chris,


First, for a basement bathroom, can someone please give me an education on what the plumbing consists of from the drain of the shower/toilet/sink to the sewer line? Most bathroom groups are roughed in like this.
Toilet connects to sewer main. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic.. The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim.

my wife had a plumber come out at one point to remedy the situation. He said (pardon my lack of proper terminology) that the drain pan was clogged up and needed to be replaced. His answer confuses me! Floor drains don't wear out and if they are clogged up you simply snake and clear the clog.

This drain is a floor drain in the mechanical room; the washer drains into the line adjacent to the floor drain, and if too much water flows down the drain, it backs up into the floor drain
This tells me that you have a partial blockage blockage downstream from the floor drain. This can be snaked from,1) the washer stand pipe, 2)the floor drain itself, 3) the washerr roof vent. My question to you is why wasn't this done by the plumber?

Second question continued; the bathroom that was added to the basement is immediately next to the old 'mechanical room'. The PO poured a 4" slab on top of his first slab, to run his sewer lines for the toilet and shower. My wife and I would like to re-organize this bathroom, moving things around and expanding it. I would like to knock the raised slab out, and put the drain for the toilet and shower at the same grade, but I fear that it is easier said than done. Did the PO put the bathroom on the raised slab for a reason? If I knock out the raised slab and try to put the drains at the basement level, will they drain properly? Who knows why the former owner made a second pour ? Perhaps it was easier to run his drainage over the old floor then it would be to jackhammer it up. You're heading into major surgery by,
First tearing out the existing floor and plumbing and carting that away and then having to do the same thing to the old floor to install your bathroom.
It would seem to me a much simpler solution would be to trench into the existing plumbing and tie your new bathroom group to that. Is there any reason you can not do that? That way you would only have to deal with taking up one floor. Your thoughts? Good luck, Tom

Good morning Chris,

Most bathroom groups are roughed in like this.
Toilet connects to sewer main. Lavatory connects to toilet drain and runs a vent off the top the stubout tee out the roof or revents back into a dry vent in the attic..The toilet wet vents through the lavatory vent and the tub/shower connects to the lavatory drain and is wet vented by it. This is a normal rough in and is acceptable both by local and state codes and also The Standard Plumbing Code Book in 90 percent of the country. Check your local codes to make sure you're not in the excluded 10 percent.. The vent off the lavatory may be run out the roof or revented back into a dry vent in the attic or if you're reventing back into a fixtures dry vent you must make your connection at least 6 inches over that fixtures flood rim.
His answer confuses me! Floor drains don't wear out and if they are clogged up you simply snake and clear the clog.

this tells me that you have a partial blockage blockage downstream from the floor drain. This can be snaked from,1) the washer stand pipe, 2)the floor drain itself, 3) the washerr roof vent. my question to you is why wasn't this done by the plumber?


Who knows why the former owner made a second pour ? Perhaps it was easier to run his drainage over the old floor then it would be to jackhammer it up. You're heading into major surgery by,
first tearing out the existing floor and plumbing and carting that away and then having to do the same thing to the old floor to install your bathroom.
It would seem to me a much simpler solution would be to trench into the existing plumbing and tie your new bathroom group to that. Is there any reason you can not do that? That way you would only have to deal with taking up one floor. Your thoughts??



Thanks,
Good luck, Tom

To clarify, the plumber DID snake it and make it better. However, he said that the "drain pan" (or whatever it is called) was a VERY OLD style drain, i.e. they used to do it a LONG time ago (house is circa 1928 and this is when it was installed).

We just had it snaked and a fiber-optic inspection all the way to the main (the tie-in to the main was repaired in May of this year). However, the snake and fiber-optic inspection was performed from the shower drain because they couldn't get the snake or the probe into the floor drain in the mechanical room because it couldn't fit. Multiple plumbers have tried and failed over the past years, they always to go the shower drain.

Help me understand "trench the floor".