Well I have started into my basement shower remodel.  I would like to maintain as much shower space as possible.  One wall is a concrete wall.  No sign of moisture migration.  I am going to apply a latex vapor barier material as a precaution.  I was planning to fastening furring strips to the cement and then scew my moisture resisant S/R to the stips, but I would prefer to adhere my moisture resistant sheet rock directly to the cement wall.  Any thoughts on if this is feasible and what type of adheseve to use.

Thanks for any help.

Johnny C

John, I would apply Laticrete Hydroban to the concrete wall, then pt furring strips then MR board, cement backer board would be better with more hydroban on the cement backer board after in applied fiberglass tape embedded in thinset. 

Most would think this is probably overkill but that's how I do it, although there are no basements in Florida so I would leave out the hydroban on the block wall.

Green board seems a bit iffy to me. I would use some type of backer board.

Thanks, Nom and Andy.

I think that I have decided to use the furring strips, partly because it will allow easier installation of the shower head plumbing.  I won't have to make a notch in the concrete wall for the piping.  Norm I will be using a product called Dryloc on the concrete wall, just as a precaution.  When I tore out the old tile shower the mud scratch coat was applied directly to the cement.  I saw no evidence of moisture but I just want to be sure.

I certainly appreciate the hydroban, cement board, mesh tape in thinset and more hydroban, especially if I were doing ceramic tile again where moisture coul still get through the grout lines.  In this case the walls will be seamless solid surface.  I just need a surface to attach the panels to. 

Andy,  why do you think greenboad is iffy?  Little to zero chance of water getting to it.  Personally I would think zero.

Johnny C

Saw this today, I guess it'll be cement board or similar.

IRC Greenboard Code: The 2006 International Residential Code (IRC) states in Section R702.4.2 that "Cement, fiber-cement or glass mat gypsum backers in compliance with ASTM C1288, C1325 or C1178 and installed in accordance with manufacturers� recommendations shall be used as backers for wall tile in tub and shower areas and wall panels in shower areas." The 2006 IRC also states in Section R702.3.8.1 that "Water-resistant gypsum backing board [Greenboard] shall not be used where there will be direct exposure to water."

Johnny C

p.s.  Curious though, a fiberglass tub enclosure can be install right against the studs.

If you have a fiberglass surround, it won't be in direct exposure to water because the fiberglass is water proof.

Tile surrounds are in direct contact with water and was used all the time. Water would penetrate the grout and rot the green board.

John, I like the cement backer board because you know it wont fall apart. It's not only from the chance that the shower will leak but also from condensation building up between the cold basement wall (exterior) and the heated interior.

Posted By Norm Walters on 10 May 2011 05:44 AM
John, I like the cement backer board because you know it wont fall apart. It's not only from the chance that the shower will leak but also from condensation building up between the cold basement wall (exterior) and the heated interior.

Yeah, might be something to that.  I just bought my cement board today.  Just so I can say I did it that way.

Johnny C

Here are some photos of the demolition of the existing shower.

The existing shower was cutured marble that installed 24 years ago.  I got tired of having to strip out the silicone and re-caulk every couple of years.  It was 34" x 42". 


Under the cultured marble was ceramic tile with a mud and metal lath.  No shower pan liner.  I guess the figured they didn't need it since they were on concrete in the basement.


Cast iron drain stack from upstairs bathroom.  Notice the cleanout facing the shower.  That is why the shower was only 34".

Last December the water heater developed a leak.  It was located where the trash can is now.  It was very difficult to gain access to and service so I moved it far to the right (out of this photo) under a stair well.

The old drain was about 3" from the existing tile wall.  I wanted it moved more toward the center of the shower.  Also at the far right of the photo you can see a cast iron vent pipe that is right in the middle of the floor space of what could be nice storage area under an existing stair well.  Bummer.  That vent is going to move.


Now that I have dug down to the old piping I can see what needs to be done to get what I want .


I capped off the vent pipe and ran a new one so that it would be inside of the wall.  New drain and P-trap near the center of the shower area.  Now I am happy.  The vent pipe under the stairs has annoyed me since we bought the house 24 years ago.


I didn't get a photo but I also replaced the cast iron drain stack and installed a new clean out 90 deg. left so that I could push the shower right up against the stack for more room in the shower.  It's finished size will be 42-1/2" x 53".

Shower pan progress in the next installment.

Johnny C

John, do a mortar pre slope before you put the shower pan liner in, that way the water doesn't just sit in the mortar bed, it will run towards the drain.

Posted By Norm Walters on 18 Aug 2011 10:51 PM
John, do a mortar pre slope before you put the shower pan liner in, that way the water doesn't just sit in the mortar bed, it will run towards the drain.

and don't forget to fill the shower pan with water for 24hrs... lol  right Norm?

Actually you are probably doing a solid surface shower pan, if that's the case ignore my last post.

Posted By Norm Walters on 18 Aug 2011 10:51 PM
John, do a mortar pre slope before you put the shower pan liner in, that way the water doesn't just sit in the mortar bed, it will run towards the drain.

Norm, you are right.  That is how I have always put a pan liner on a mortar bed.

And you are right again.  In this case I am going to use a Solie Surface pan.  Walls and ceiling also.

stay tuned.

Johnny C

Here it comes people.   Look away if you are bored with pictures and details.

This is the form for thermoforming the floor.  It has a 5/16" pqr ft. slope to the drain.  The outside perimiter of the form is spaced away from the floor so that I can make the SS pieces slightly oversized.  I also make the perimiter pieces of the mold 1/2" higher than the floor of the mold so when I apply the vacuum blanket it would curl down the edges.



After thermoforming and trimming the floor to the exact size I cut a piece of PB so that it was 1" smaller than the finished floor.  then I used a 1" collet and a 3/4" bit to go around the edge to make a 1/8" x 7/8" rabbet for the cove build up strip. 


I pre coved the pan before adding the apron around the sides.  I Used a 3/4" core box bit and a fence attached to the base.  I actually have a bonifide rounter fence but it takes longer to set up than just hot melting a temporary fence directly to the base.  Set the router to that is just a sliver above the surface of the sloped floor and run the router around with the fence to the outside of the pan.


I pre-made the corner seat.  The outside corners are V grooved beveled on the table saw.  It is not done yet in this photo but I also pre coved the seat before assembly.


OK, I am busted.  I have a bit of a mess going on around the work area.  Here I am attaching the corner seat and the pre-made curb (front top and inside face).  The top of the curb has about a 1/4" slope on a 4" width.




I added an apron around the sides and also on top of the corner seat so that when I glue the wall panels in place I won't have to deal with the cove area.  Oh, I forgot to mention that when this shower is finished it will be totally coved.  The only place that will have a caulk line is at the ceiling.


To be continued...

Johnny C

That is sweet! Love the step by step pictures. That will be one of the nicest basement showers in all of Oregon!

Great detail.

Is this entire system going to be floating in the shower opening and only siliconed to the studs?

I have hear some fabricators have trouble with the cove breaking.

Posted By John Christensen on 19 Aug 2011 03:57 PM
Here it comes people.   Look away if you are bored with pictures and details.

This is the form for thermoforming the floor.  It has a 5/16" pqr ft. slope to the drain.  The outside perimiter of the form is spaced away from the floor so that I can make the SS pieces slightly oversized.  I also make the perimiter pieces of the mold 1/2" higher than the floor of the mold so when I apply the vacuum blanket it would NOT (EDIT) curl down the edges.


I did not proof this post well.  I have added the work not into the text.

Johnny C

Ready for some more?

The last part of the pan assembly was adding reinforcement at the cove transition area and the joint where the walls would seam to the pan.  I didn't get a photo of that but this cross section drawing will give you the idea.

The cove detail was done with the single rabbet technique.  I thought that it would be advisable to add reinforcement there.


Because the the wall sections would be to large to handle, I set the lower section of the walls in place, prior to fabrication of the whole wall, leaving a 3/8" gap.  This was to allow me to do a mirror cut on the entire seam includiing the step up to the seat.  I secured them into position with spanners using hot melt.  The spanners have a relief cut in them for the router bit to pass.


This is the back side of the wall.  I set up straight edges above the seat and to the left of the vertical seam so that I could run a 1/2" bit through startiing at the far right and stopping at the bottom corner.  Then I set up a straight edge below the bottom seam and stopped the router at the tight corner.  With care you can get the stopping points to be very close.  The inside corners needed to be hand fit with a sanding block to fit the radius of the cut made by the router bit at the outside corners. 


Once all the bottom sections of the walls had been fit to the pan I completed fabricating the walls.  The space for the walls was templated so that the walls when finished would match in size and squareness to the space they were to be installed.  I needed to have a verticle site seam on each wall.  I made each section 1/2" wider than needed and then ran a 1/2" bit through the seam location to cut the panels and create the perfect seam.

I didn't want any of my site seams to be at the coved corners.  I made all the wall seams at least 6" from the corners. 

The first piece is dry fit to the pan.  All wall seams have a seam stap on them also. The coves on the walls were done with the double rabbet technique.  That was in order to have overlapping joints in the cove detail.  I believe this will be enough reinforcement at the verticle wall coves.  In this photo the pan does not have the reinforcement pieces added yet.


This is the second piece in the dry fit.


All the walls are now dry fit.  I wanted to dry fit the walls before adding the reinforcement to the pan just to be sure that they would sit flush or even slight ly less than flush at the apron around the pan.  If the walls were even the slightest bit larger it would be impossible to install them after the reinforcement was in place.


Next up, installation day.

Johnny C

John you are a TRUE craftsman !

WOW great work man !!!!

I think I would hire you to do my shower instead of me. That looks like a ton of work.

Post these series of pictures on your website, they are truly remarkable.