Questions about bathroom renovation

Hi everyone,

we're redoing our bathroom and to avoid inadvertently covering up anything, we've gutted the entire thing. We knew some part of the old shower had been leaking and causing mold, which we found to be the taps (leaking inside the wall...). Also the toilet seems to have leaked at the wax ring some time ago so the underfloor was moldy. Anyway, all ripped out now.

We have a few questions about some of the plumbing aspects of the work. I hope I put in enough detail...

1) There are two cavities inside the concrete under the floor. The one of them has a 4" cap on it, and when I opened it I found a backflow device. The backflow device allows water to flow from below and into the horizontal pipe. I don't really understand when this one is used as we ran some water down the pipes in the area and never saw any water go through there... Any ideas? The other cavity only has dirt and concrete in it, seems to serve no purpose. Image is below:



2) Based on the answer for above, what are your thoughts on flooring over this? We are thinking of installing tiles with heat, but based on what access is required to this backflow device, it could impact the flooring type.... Since I've lived here I certainly have not had to access it.

3) The copper piping serving the fixtures seems to be pure black. Touching it leaves a black powder on my fingers. Any ideas on this? The image below shows the pipe and manufacturer:



4) I removed all the subfloor (~3/16" plywood) and linoleum under the flange, and what I am left with is shown in the image below. My question is, I want to install tiles, and I feel that the subfloor and tiles will not fit under this flange. Can the top of the flange be flush with the tiling? Or do I have to somehow get the flange raised?



5) For the shower drain, there's a few questions. The image below is what the questions are about.
5a) Should there be sand around that ABS pipe at all? Or is it OK as shown?
5b) The new shower we are installing will be larger and the drain won't be in the exact same spot. My thoughts are to jackhammer out the concrete a bit and just extend the horizontal piece of pipe to accomodate the new location. Might have to put in a slight 22.5 degree bend, not exactly sure. Should that work?

I know replying to my own thread isn't really classy, but I know more photos help, so here they are:
***********************************************************************

6) The image below shows the supply and drain for the vanity/sink. This is an external wall (basement, concrete is behind the insulation). What is the deal on running supply piping in an external wall? Should I insulate the pipe? Should it be run between the drywall and vapour barrier (somehow I don't think so but someone please enlighten me) With the constraints on sizing in that bathroom the natural spot for the vanity is on the outside wall...



7) Also, with reference to the picture above, the sink drains down into the ABS pipe shown. There is no vent going up above. Is that still OK? I believe the vent near the shower is this drain's vent. There's about three feet between the shower and the sink drain. Let me know thoughts on this one.

8) The image below shows a 4" pipe with cap as well as some type of bolt head. Any idea the purpose of this 4" pipe? A cleanout? Basically where it is located leaves us no choice but to box it in? And the round thing with a bolt head, is that a water shutoff of some sort?



9) Maybe this should have been asked first, but here it is. The image below shows the overhead layout of our washroom. It is not complete as I don't quite know what's going on underneath the concrete. I'll write below what I do know:

• The toilet pipe goes in the direction shown based on what I can see looking down into it
• The sink drain goes in the direction shown and the into the concrete, as seen in the photos above
• In the cavity with the 4" pipe with cap, there is a 4" pipe that goes towards the left (there is a finger mark on the pipe as shown in above photo) which is not part of the backflow preventer. The backflow preventer prevents horizontal fluid from going downwards.
• The 4" cleanout near the shower is the one shown in the photos above.

Maybe it will be obvious to someone else how all these are connected? I'm wondering where the city drain gets connected?

I'm going to comment on supply piping on an exterior wall.

You can insulate the piping if you wish, but insulating it will only help with heat loss, and sweating. It is NOT there to protect the pipes from freezing, if they're on the exterior wall.

You should make sure you have as much insulation as possible behind the piping.

You should make sure the piping is on the drywall side of the vapor barrier.

I'm really confused about the drain for the lav, it isn't even below the slab...?

dlarrivee said:

I'm really confused about the drain for the lav, it isn't even below the slab...?

Click to expand...

I was slightly confused when I saw that as well. The photo I posted cuts it off, but the drain slopes down into the concrete. Right before it goes into the concrete it 45 degrees downwards. The vanity, being that it has a ~3" pedestal, covered all that up... I just hope I have no problems finding a vanity that does the same.

lucgallant said:

I was slightly confused when I saw that as well. The photo I posted cuts it off, but the drain slopes down into the concrete. Right before it goes into the concrete it 45 degrees downwards. The vanity, being that it has a ~3" pedestal, covered all that up... I just hope I have no problems finding a vanity that does the same.

Click to expand...

I don't think you're going to end up leaving that drain in such a configuration anyways.

Every fixture needs to be vented.

Generally in Canada a "wet vent" is done with 2" through the lav...

The vapor barrier is the last thing on the wall before you drywall. Pipes are always behind the vapor barrier unless your vapor barrier is the foil that is stuck to fiberglass with tar.

The lav used a vent 90" at the bottom? That should be a long turn 90 el.
It's not vented.
Is the toilet vented?
Is the shower done in 1.5" or 2"?
The plate with the nut on it is a mechanical plug. Somebody put it there. I would remove it and see if there is a better solution. There may not be.
The toilet flange need to be attached to concrete before the toilet is set. It doesn't have to be above the tile. I know it's best when they are, but it still works at the lower position. Unless the flange is "above" the finished floor, I use two wax rings.
We set hundreds of toilets every year that way. Been doing that since 1974, so don't bother arguing that one with me.
Back flow device. I would want to know a lot more before that was covered. If it ever needs replacement, it should be accessible.
Most times, a back flow is installed if the plumbing is below the public sewer system. It prevents the neighbors waste from flooding your lower floor. Many homes on lake front have this issue. The manhole cover is above the lower floor, so in case of a plugged main, it backs up into the homes. My brother in law worked for the water and sewer in Bellevue, it happens all the time.
Black stuff on pipe, that's a new one. Never seen it.
The ABS cleanout? You have to have one. I don't see a plumber just throwing one in unless it was to meet plumbing code.

I will just address the "backflow valve" question, because all the rest is too laborious to analyze. It is a "cleanout tee" with a raised square head plug. It has NOTHING to do with backflow prevention or keeping the water flowing in the right direction. DO NOT seal it so it is inaccessible.

Thank you everyone for your replies, very much appreciated. I will try and give answers to all that was asked.

dlarrivee said:

I'm going to comment on supply piping on an exterior wall.

You can insulate the piping if you wish...

You should make sure the piping is on the drywall side of the vapor barrier.

Click to expand...

So are there plumbing codes about running piping on an exterior wall like this? The piping has been there 20 years and shows no signs of freezing. I also intend to put in 2x6 walls with R20 instead of the 2x4 walls there now.

dlarrivee said:

I don't think you're going to end up leaving that drain in such a configuration anyways.

Every fixture needs to be vented.

Generally in Canada a "wet vent" is done with 2" through the lav...

Click to expand...

So unavoidably then I have to run a vent line up through the ceiling and connect it to the shower vent in the ceiling, correct?

Terry said:

The vapor barrier is the last thing on the wall before you drywall. Pipes are always behind the vapor barrier unless your vapor barrier is the foil that is stuck to fiberglass with tar.

The lav used a vent 90" at the bottom? That should be a long turn 90 el.
It's not vented.
Is the toilet vented?
Is the shower done in 1.5" or 2"?
The plate with the nut on it is a mechanical plug. Somebody put it there. I would remove it and see if there is a better solution. There may not be.
The toilet flange need to be attached to concrete before the toilet is set. It doesn't have to be above the tile. I know it's best when they are, but it still works at the lower position. Unless the flange is "above" the finished floor, I use two wax rings.
We set hundreds of toilets every year that way. Been doing that since 1974, so don't bother arguing that one with me.
Back flow device. I would want to know a lot more before that was covered. If it ever needs replacement, it should be accessible.
Most times, a back flow is installed if the plumbing is below the public sewer system. It prevents the neighbors waste from flooding your lower floor. Many homes on lake front have this issue. The manhole cover is above the lower floor, so in case of a plugged main, it backs up into the homes. My brother in law worked for the water and sewer in Bellevue, it happens all the time.
Black stuff on pipe, that's a new one. Never seen it.
The ABS cleanout? You have to have one. I don't see a plumber just throwing one in unless it was to meet plumbing code.

Click to expand...

So I'm a little bit confused now as to whether the pipe goes on the drywall side of the vapour barrier or the insulation side...

Here is a picture of the sink drain:


When I look into the toilet drain it goes straight down for about 2.5' and then turns. I guess that would mean it is not vented? My thoughts are that the toilet piping is all original from the house because it is encased in concrete and goes down 2.5'... Let me know thoughts on if this is OK.

So between the flange and the concrete there is a 1/2" gap. What should I put between that gap before attaching it to the concrete?

The shower is done in 2" ABS.

So the mechanical plug, what would be its purpose?

A picture of the backflow device is below. I looked inside of it and the under the flap the pipe goes down for about 6" and then elbows off. There is water sitting there under the flap. Could it be weeping tile? The horizontal part goes horizontal (towards the other cavity) and then elbows down to the main sewer (I poured a bit of water down and I can hear it drip into other water)

Still unsure of that other elbow visible in the photo...



As for the 4" cleanout, I opened it and found it elbowed down right away.

Last question of this post, regarding accessibility of these cleanouts and cavities. The cleanout will have to be boxed in somehow although it will be partially in the wall.

As for the cavities, the flooring has to go right over top as far as I can see. Whether it's linoleum, tiles, or some other flooring, it's all going to "seal" it, isn't it?

I uploaded some more photos to give people a better idea of how things are laid out.




Again thank you very much!

I was talking about the supply piping, and it should ALWAYS be on the drywall side of the vapor barrier.

Terry, this guy is from Fort McMurray, not Seattle... it actually gets cold there.

dlarrivee said:

I was talking about the supply piping, and it should ALWAYS be on the drywall side of the vapor barrier.

Terry, this guy is from Fort McMurray, not Seattle... it actually gets cold there.

Click to expand...

Perfect, thanks. That's how it is currently setup. dlarrivee is correct about it getting cold here, on the Environment Canada website last year we hit -52 C (-62 F) with windchill.

I think I got a handle on things now, the only thing I'm still curious about is whether the toilet pipe is properly installed. Like I said before, it goes down for about 3.5' and then hits the main line. I know it is the main line because doesn't matter what I do water wise in the house, I can hear the water flowing by if I listen in. I guess strictly speaking it has no vent? Or is the shower vent adequate? I will post a diagram shortly of what how I believe things are laid out.

As promised, here is a diagram of the layout.

This is an external wall (basement, concrete is behind the insulation).

Click to expand...

Is the basement above grade or below grade. If it's below grade, then it will be earth tempered. That would be why you haven't had freezing issues.
"There is concrete behind the insulation" Did anyone else read this comment?
And a vapor barrier is not insulation. Here in the lower 48, the vapor barrier goes on last. It's only purpose is to prevent inside moisture from getting the insulation damp. Outside air is drier.

Terry said:

Is the basement above grade or below grade. If it's below grade, then it will be earth tempered. That would be why you haven't had freezing issues.

Click to expand...

Hi there,

the basement is below grade. About 1' of the piping is on the exterior wall without earth on the other side. The rest has earth on the other side...

Thanks again.

That "flapper thing" is completely incomprehensible, because from the way the picture looks, it lets water flow UP to the floor but would keep it from flowing down.

Is there a vent above the 1.5" lav, in the proposed bathroom?
I didn't see one, in the hand drawn sketch.

--

Winter snow covers the 1' distance above "earth".

--

Terry said:

Is the basement above grade or below grade. If it's below grade, then it will be earth tempered. That would be why you haven't had freezing issues.
"There is concrete behind the insulation" Did anyone else read this comment?
And a vapor barrier is not insulation. Here in the lower 48, the vapor barrier goes on last. It's only purpose is to prevent inside moisture from getting the insulation damp. Outside air is drier.

Click to expand...

All exterior walls should be treated the same, you don't want to be telling people there are different rules above or below grade.

What makes you think putting the piping on the insulation side of the vapor barrier is a good idea?

hj said:

That "flapper thing" is completely incomprehensible, because from the way the picture looks, it lets water flow UP to the floor but would keep it from flowing down.

Click to expand...

hj,

In the picture with the flapper, I removed the 4" cap. So if water were to flow up through the flapper, it would flow to drain. I coudln't go to the floor because the cap would be on. Not sure if that clarifies it?

geniescience said:

Is there a vent above the 1.5" lav, in the proposed bathroom?
I didn't see one, in the hand drawn sketch.

Click to expand...

Well the bathroom in the pictures existed before we tore it down. There was no vent above the lav. I will be installing one when I redo the bathroom. The hand drawn sketch shows what is currently in place, not any future additions.

Any ideas on the toilet venting?

Terry said:

Is the basement above grade or below grade. If it's below grade, then it will be earth tempered. That would be why you haven't had freezing issues.
"There is concrete behind the insulation" Did anyone else read this comment?
And a vapor barrier is not insulation. Here in the lower 48, the vapor barrier goes on last. It's only purpose is to prevent inside moisture from getting the insulation damp. Outside air is drier.

Click to expand...

Hi Terry,

maybe I was unclear. As shown in the picture above, there is drywall, then the piping (both supply and drain), then vapour barrier, then insulation, then concrete. So there is concrete behind the insulation, and the insulation is behind the vapour barrier. Hope this clarifies things. I usually express myself in a backwards fashion... Thanks again for all your assistance and patience.