Tuesday, May 23, 2017

Master Bath Shower Remodel

I wanted to post an in depth overview of how I approach a shower remodel from start to finish. I will show you how I created a waterproof barrier, allowed for expansion while maintaining its shape and function and talk about how water moves in a shower and the walls of your home. As a bonus I will detail about some of the special considerations and unexpected issues I encountered with this and the solutions I applied.

Above is how it looked after tear out, and to the right you can see how I modified the framing to accommodate the Onyx Collection shower caddy. The diagonal pipe you see is from their A/C unit and acts as a drain for condensation. The homeowner was ready to move the caddy to another wall before I showed him how this could be done.

With the Onyx Collection shower base they had selected we had a choice of moving the drain plumbing or furring the back wall the width of a 2x4 and cutting the existing floor tile a little to fit. We did the latter. I placed 2x4s 16" on center horizontally to add some strength and protection from future shifting. I was careful to allow over 3/16" in all directions for the drain pipe from the upstairs shower. Surprisingly this exterior wall had no insulation which I made sure to add.

There was one copper supply line protruding at the base of the wall which I decided to work around to avoid any potential for damage and leaks. Some would want to pound it out of the way, but I would advise against it as this could lead to an especially expensive to fix inside the concrete slab and could have cost the homeowner in both extra water and electricity before it was discovered since this one was the hot water supply line.

Next came the Hardie Backer board the customer had opted to use. In order to work around the copper supply line I mentioned I had to score a small channel in the back of the lowest part of the Hardie Backer board. I would later use a thicker application of mortar for the tile on this side to fully correct the finished tile.

After furring the back wall there was no structure to fasten the edge of the adjacent wall. I ripped scrap 2x4 in half lengthwise and using roughly 16" lengths in a few spots I then attached 2x4 vertically in the corner to secure this edge of the board as shown to the left.

Once all the board was fastened I used alkaline resistant mesh tape on the roughly1/8" seams which I then filled with modified mortar. The gap at the seams allows for movement without compromising the structure and the modified mortar acts to fill the gap for waterproofing while still allowing it to flex without buckling or bulging.

While doing this I also covered all screw heads with the same modified mortar. This is to make the surface easier to waterproof. The next day I used a rubbing stone to remove any loose mortar and smoothed the surface, making a more ideal substrate shape for tile. 

Next I waterproofed the walls using AquaDefense made by Mapei. I carefully applied two coats (used a full gallon), sandwiching fiber matting strips in the corners and over all seams where Hardie Backer board meet. This acts to create a durable layer of a latex-like material which is flexible, stretchable and waterproof. The fiber is used to increase the durability of the membrane in the areas most likely to fail. The product is also designed to be a good substrate material for tile work.

Now for the tile work!

The most important step of a successful shower tile install is creating at least a 3/16" gap between the bottom of your vertical tile and the horizontal base below. This will later be filled with chalk, usually a color match of the grout. This is done to allow your base and walls to move relative to each other without cracking, buckling or other stresses causing the tile to fail as well as to keep the grout out of any standing water which it could then transport up or along the wall. It is a good idea to keep grout lines small and seal them in any direct water installation also.

Another important note is the placement of your board relative to the base. You will want to allow at least a 1/4" gap from the top of the base (including the flanges if using a manufactured base) to the bottom of the board. This is done to prevent water from climbing from base to wall behind the tile and becoming trapped.

There are books written solely on how water travels in a home, how geography, climate and even the direction of the sun affects how water will behave and the best building practices to manage water migration. Here I will simply say homes breath much more than most people think and moisture is present in practically all outside air at nearly all temperatures. Problems with moisture in homes usually only manifest when it has no route to escape through evaporation and is trapped as a liquid. This is why most homes in the southern part of the US do not use a complete vapor barrier on either the inside or outside of the external wall cavity.

Ok, back to the tile:

I know, I skipped a lot. Like how I used a laser level to pattern the tile from the center of the drain and counted courses to plan how the shower arm (the little pipe for the shower head) would land in the center of a tile rather than on a grout line. How I used a 4' level and a suction cup to keep the tile vertically plumb and the 1/2x1/2x1/2 trowel I used across the short dimension of each tile to eliminate as much air in the mortar as possible for the best adhesion. I also cleverly used scrap tile as the substrate for the mosaic at the top instead of floating it into a deeper mortar.  Anyway, there you have it for now.

Wait, what is up with the wall cap? is it really bigger at the top than the bottom? Not for long!

This is one of the issues I came into during the install. It turns out both walls are parallel, but both are also leaning left. There are many ways this could have happened, but to correct how this looks I used a new corner bead on the lower left side and along the middle and upper shower side. Using drywall compound to feather the wall on the left side and fill the corner on the shower side I created a consistent and plumb wall cap. This also required removing and replacing the baseboard.

To finish I filled all angle joints with color match chalk, grouted the tile work, inserted the caddy with clear silicone and sealed the outside edge with color matched chalk. I later installed the door by carefully drilling holes into the tile using a specialized drill bit with diamond dust similar to what dentists use and inserting wall anchors to fasten the rails. I completed it by sealing all edges inside and out with clear chalk. Feel free to comment or contact me if you have any questions or would like my services.

The homeowners have told me they are very happy with their new shower and commented specifically on how much they appreciate the extra attention to detail. I really enjoy what I do.

All pictures posted were taken and posted with the consent of the homeowners

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