Aaron's Basement Bathroom Project [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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03-04-2007, 01:20 PM
First and foremost, this site is unbelievable! The amount of information here is amazing, and the responses are quick, friendly, and easy to understand for DIY'ers like myself. Great site John!

Ok, so I have a house in Pittsburgh built in '52 with a corner shower in the basement. The shower was built out of concrete block with some kind of premade pan installed under the block. The pan itself developed a crack around the inside perimeter, causing leaks everytime the shower was used. The bottom line is that it needs replaced. So I am redoing the whole bathroom. I love to tile, and I like the look of tile vs. the prefab surrounds. I figured this would be a good project to tackle. I already made some mistakes with my upstairs bathroom project, but with what I learned there I think that I can get this one right. Demo'ed the concrete walls yesterday, and am pulling the pan today to see what kind of trap (if any) there is in the floor. The floor, by the way, is solid concrete. I am attaching a few pics so it is easier to visualize. The area for the shower WITHOUT framing is 60"l x 45"w x 88"h. I am planning to tile 3 walls, the ceiling, and the 4th wall with an opening (no door or curtain).

I had a couple questions for you smarter shower guys and gals that I thought would help in my planning. Of course I will have lots more.

1. Since this is a concrete slab, would it be best to make the curb out of bricks? The rest of the framing is 2x4, but should I use PT wood?

2. The drain is currently not centered in my dimensions. Should I break up the floor and center it? Or could I slope the bed with the drain off center?

3. I need to slope the first bed (1/4" per ft. right?). Which method would be best?
a. Kerdi shower and drain?
b. mortar/PVC/mortar pan with Hardi or concrete board and Red Gard?
c. mortar/PVC/mortar pan with Hardi or concrete board and 6mil Vapor
d. mortar/PVC/mortar pan withDens Shield.

4. For the ceiling, I need a Vapor barrier of some kind? Does that affect the 3 choices above?

That should be enough to start. Thanks for your help and feedback. I am pretty psyched about this project!

PS - I'll post pics when I can make them smaller. Right now they are too big.

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John Bridge
03-04-2007, 06:25 PM
Hi Aaron, :)

No pressure treated wood in the shower framing.

No moisture barrier on the ceiling unless it's a steam shower.

Drain can be off-center as long as it's not close to a wall or curb.

Kerdi is used only in a complete Kerdi shower. Red guard is better than poly. :)

03-04-2007, 06:58 PM
WOW! Can't believe I got an answer from "the man" that quick. Thanks John! I thought that I had read that the blocking in between the studs (2x6's?) for the membrane were PT. Guess I read wrong.

03-05-2007, 05:50 AM
I have been reading about curb installs for showers, and since I am putting this shower in the basement on the concrete slab, I believe brick is the suggested marterial for the curb. Am I correct? 2 Quick questions with that:

1. What is best to adhere the brick together AND to the floor? It will be sitting in between 2 2x4 framed walls. OR should I scrap it and use 2x4's?

2. When it comes time to install the pan and I am putting the membrane over the curb, usually I see the outside of the lath stapled or nailed to the curb. Being that this is brick, how should I attach the lath? Or should I just preform and try to keep it as close to the curb as possible without attaching it?

Thanks again for the info!

03-05-2007, 04:10 PM
Pictures are coming... promise.

So I pulled the pan out, and sure enough the old pan had a pipe that ran into the drain of the basement floor, but only sat in the drain...it wasn't connected in any way. Anyone run into something like this? Guess I'm going to have to break the concrete to get to the trap? I know, a picture is worth... their coming.

I have been doing a little $$$ figuring. I thought initially that the Kerdi system would be too expensive. After a little math, it seems like the Kerdi would be less expensive than going with a traditional shower setup (i.e. 2 mortar beds, pan liner, hardi, Red Gard). Does this sound right to those of you that have installed both? Could it be less expensive? :scratch:

03-05-2007, 08:35 PM
Don't forget the drain Aaron. By the time you add in the $90 Kerdi drain I doubt it will cost less. Close to the same possibly comparing to a RedGuard waterproofed shower, but not less.


03-05-2007, 08:54 PM
Thanks for the reply Mike! I kind of thought the same thing, until I started crunching numbers. Checked around and found this for a Kerdi system:

Based on a shower with approx 110 ft2 of area to cover, including 3 1/2 walls and pan PLUS curb, Stainless drain, and 4x8 drywall I came out to about $350.00 - looked at Tile Experts site and figured on the 162 sq ft roll.

Based on $4/sq ft PVC liner, 3x5' hardi or wonderboard, redguard (which JB recommended over poly)...

Wait, I think you are right. OK, but the difference isn't that great. Maybe $60-$80. Is the Kerdi that much easier to justify the expense? FWIW I don't think the expense is too great if it will cut time and be easier to install.

03-05-2007, 09:19 PM
I went from walls and drain ready to go to a waterproof system in about 6 hours on my first shower...it was worth the expense.

03-05-2007, 09:40 PM
ok, finally got some pics down to size to post. I know that you will be tempted to laugh at the shower, especially the pan and "quick fix" caulking around the edge. :bonk:

03-05-2007, 09:49 PM
I pulled the pan with 2 crowbars. It WAS NOT attached to the drain plumbing in the floor. Instead, the pan, which feels like 3" of solid concrete, has a small 6" long drain pipe that just "fit" into the drain in the floor. I'll post pics when I return home from traveling. There is water in the drain in the floor, so I am assuming there is a trap there.

Does this mean I'm gonna have to break the floor to see what my trap looks like?

Since this was built in '52, there obviously is no PVC in the ground. How would I go about fixing that drain (I have done some plumbing in the second floor, not in concrete where I can't see the bottom)? Is it time to call someone who knows what there doing?

03-08-2007, 06:42 AM
Ok, I think that I may have gotten the plumbing handled. I have a plumber friend coming to have a look at my drain. On to the rest. I know this isn't necessarily a "carpentry" forum, but since it will tie into how I do the walls, I figured I would ask.

As a recap, my shower is going into the corner of my basement with 2 concrete block walls at a somewhat 90 angle. Haven't decided if I am using Kerdi or going with traditional pan and CBU. On the wall where the water lines will be running, I am going to use standard 2x4's to give me a little room to run the lines in between. This is one of the concrete block walls. The second concrete wall is where the majority of my question lies. Obviously I will have a top and bottom plate that will attach (screwed?) to the joists above, which are 16" centers. I am planning on using tapcons on the bottom plate and on the studs. So that would mean that I can't use a 2x4 for the studs, as I would need a pretty long tapcon to even touch the wall. Should I use 2x2's, and will they be strong enough to support the CBU and/or drywall (Kerdi) and tile? If you have a look at this site:


you can kind of get an idea of what I am looking for. Any other wood size suggestions? Just wanted to check with more "qualified" DIY'ers and Pros. Thanks!

03-08-2007, 07:02 AM

I am finishing a basement bathroom shower that has a cinder block wall on one side. I used tapcons to attach 2X4s sideways, 16" on center.

03-08-2007, 07:05 AM
Thanks Dan. So I assume then that you will only have 2" (1.5" really) of depth on the stud to screw into. Just wanted to check if that would suffice. Thanks!

03-08-2007, 07:11 AM
So I assume then that you will only have 2" (1.5" really) of depth on the stud to screw into.

Yes. But that's enough. I used 1 1/4" Rock-On screws, (which are rated for attaching 3/4" board) to attach 1/2" Hardibacker.

03-11-2007, 08:39 PM
Pulled my old pan from the floor, and it lookf like I have to jack out the floor to fix the trap before I can attach a new drain. I guess on the bright side it allows me to move the drain to the center.

So I am thinking about the curb now, and I understand that because this is a concrete floor that I am using as an initial substrate, I need to use brick for the curb. 2 Questions about this:

1. Am I just to use brick mortar for the brick curb, and should I apply a thin-set before the mortar to adhere the brick to the floor?

2. The brick curb will be sitting between 2 framed walls. Should I adhere the brick to the 2x4's on both sides in any way?

Thanks for the info!

03-11-2007, 08:52 PM
Hi Aaron, use thinset to adhere the bricks to the concrete. Don't worry about the wood framing cuz you'll wrap that with drywall and Kerdi.

03-12-2007, 11:38 AM
Another question (of course):

I understand that I need to use a thinset to adhere the mortar for the brick curb AND for the first pre-slope layer for the pan. I have been reading about this in every place that I can (and I did order TYW, great book!). I have heard it explained that I need to mix the thinset, apply it to the floor, then apply the mortar overtop. But I also read that you can mix the thinset with the mortar itself and apply it. Is that the case? Am I reading into this too much?

03-13-2007, 06:46 PM
OK, I'm back. Figuring out the picture thing a little bit more as well.

1. I have a crack in my slab that is about 17 inches long, but ONLY the width of a mark on a tape measure. The slab's been there since '52. Do I need to worry about the crack?

2. I tried to drop water on the concrete (per Daltile guy) to see if it beads or soaks (he said it need to absorb). It seems like it did. Even so, if a slab was "sealed" over 50 years ago, could it still be sealed? Should I be concerned with "scoring" the slab?

3. The Daltile guy today told me to add a Latex additive to the thinset to adhere the deck mud. Sound right?

Thanks all!

The pan weighs over 200lbs, easy! Check out the drain. Guess I need to rent some equipment to dig up the slab!

03-13-2007, 09:14 PM
Hi Aaron, right you want a modified thinset to adhere the deck mud. You need to mix it pretty loose. Use the same thinset for the bricks but regular mixture. You will need to treat the crack with some type of isolation membrane whether it be Redgard or a stick on membrane.

04-15-2007, 06:39 PM
slow going with the basement bathroom, but finally got the concrete and framed walls down. It's coming...

Just curious because of how much I have read about NOT using Mastic. What exactly is mastic good for? Anything?

04-15-2007, 07:52 PM
Mastic is OK for smaller tiles on a wall in a non-wet area - a kitchen back splash, for instance. I didn't know of a single advantage it had over regular thinset until someone recently mentioned that it's good for putting up tiles that you plan on taking down soon. :yeah:

It's popular with the big box stores because it has a decent profit margin. Many DIYer's are drawn to it because it is less intimidating than correctly mixing a thinset. Heck, picking the right thinset can be overwhelming.