• Masonry Shower Seats (Benches) for Ceramic Tile Showers
– John P. Bridge (July, 2002)
See also: Tile Shower Benches/Seats
I’m a mud man. I build ceramic tile showers out of cement mortar, which is reinforced with metal lath (expanded metal mesh). It’s logical, then, that brick and mortar (or cement block and mortar) are the materials that go into the shower seats (benches) I build. I call them “monuments” because they are built up inside the shower pan liner and simply reside there. Gravity and friction hold them in place.
The tiled benches can leak, but any water that gets through one of my seats is contained by the shower pan and ultimately finds its way to the drain “weep holes” and down the drain pipe. The mud-built shower bench will work in any shower installation, including those employing the cement backer board method, as well as the new Kerdi method by Schluter Systems. It is important to note that, unlike seats built by other means, our masonry seat must be built entirely inside the shower pan. Do not build the seat and then install the shower pan in front of it. If you do that, I can guarantee it will leak profusely and cause you much misery.
Recently, Dave Misevich, of Canton, Michigan, completed a seat in the shower he is building. Dave took a series of very good photos of his progress and offered them for use here. If you click the thumbnails, you’ll be taken to the full-size versions. Muchas Gracias, amigo.
• Here’s what you need in the way of materials
– Brick mortar. This can be bagged mortar which contains sand and cement, or you can make your own from clean sand and masonry cement. I won’t go into to the finer points of making mortar here, so if you’re not sure of the process, use the pre-packaged stuff available at such places as Home Depot and Lowes. I’ll say a little more on the subject further on.
– Bricks or concrete blocks. You have to accumulate enough of these in volume to complete “fill” the seat you intend to construct. The mortar will hold them together and provide a means of “fairing” the surface of the seat so it can be tiled.
– Mason’s trowel, gauging trowel or pointer. A flat plastering trowel is helpful but not essential.
– You will also need a short level and your various tile tools. A hammer will come in handy for breaking up the blocks or bricks.
– Straight-edges. These can be short pieces of wood boards, anything that is straight and that will help you plane the surfaces of the seat/bench structure.
– Buckets, one for clean water and at least one in which to carry the mortar. Tile setters scrounge buckets any way they can, from painters, from drywall finishers — from anyone who might value the bucket less than the tile setter does. The last thing in the world a tile setter wants to do is actually purchase a bucket. It’s just not good form.
You might have to buy plastic buckets, though. Grin and bear it. Try not to end up with the ones that sport the orange label of a prominent big box store. That’s really bad form.
Materials Dave has assembled. The Mason Mix is available at Home Depot and at lumber yards.
• Making the Mortar
Brick/stucco mortar is made by mixing sand, portland cement and construction lime with water. An easier way is to buy a sack of masonry cement (Type S, N, or M) and mix it with sand and water — about 16 shovels of sand to the sack. Add water until the mix is pliable with a consistency similar to butter. An easier way yet is to buy the materiel shown in Dave’s picture above and add water to it.
Mix the mortar in a wheel barrow, a wood box constructed for the purpose or on top of a piece of plywood or hardboard. You can use a shovel or a garden hoe to do the mixing. Allow the “mud” to stand for five minutes and then re-mix it. You will have about 45 minutes to an hour of open time.
• Building the Bench
Begin by spreading a bed of mortar on the shower pan material in the area in which you wish to build the seat. About an inch of mortar is spread. Set a block (or brick) in the mortar. Align and level it. Concrete blocks are thirsty and will suck moisture out of the mortar, so don’t dilly-dally in getting the block level and straight. If the mortar gets hard before you have a chance to adjust the block to your liking, remove it and start out with fresh mortar. Dave is using a “torpedo” level.
You can now begin filling in behind the block with broken fragments of block or brick, or you can continue the front by filling the voids at each end of the block you’ve set. Let’s fill in behind the block and then move on to the ends. Drop in a couple fragments of block, and then put a little mud in. More block, more mud, and so on.
You can see that the areas on each end of the block will require pieces smaller than the first block set. Making these pieces will entail breaking a block with a hammer. It is not important how the block is broken, so long as you end up with a piece, or pieces, that will fill the voids at the ends. The pieces of block (or more bricks) are cemented to the first block with mud. The structure is also locked into the walls with mortar as it is erected. You should dampen the walls with a sponge before applying the mortar. This will keep the backer board from drawing moisture from the mortar prematurely. We don’t want anything really wet, just damp.
The mortar will not stick to the backer board well. It will, however, lock into the tiny pits and crags of the surface and harden. That’s all it takes.
This doesn’t have to be a work of art. The only important thing is keeping the structure straight and plumb at the front. This is important.
Dave uses a straight-edge to check the front of his handiwork. You’ll notice structure straight and plumb at the front. His buckets are free of identifying logos. This is important.
When the lower portion of the bench has been “roughed in,” you can continue on to the next layer or “course” of blocks. We are using blocks that are eight inches tall, so two courses will do the job. You can make the seat a little higher by adding fragments of block to the top.
Having laid a bed of mortar, Dave sets the block. He will immediately level the block and plumb its front with his level. The second course of block or brick is completed in the same manner as the first. Fill in the ends as best you can with fragments, and toss the remainder of the rubble into the block “cells” or behind the larger pieces. Use plenty of mortar to tie everything together.
Now, unless you are highly skilled, or have been extremely lucky, the front of your bench will not be perfectly plumb and straight. You can rectify this by “floating” additional mortar onto the front of the block structure and striking it smooth and straight with a straight-edge.
It is essential that the front of the bench be flat or “on plane,” and it is also important to keep it plumb or vertical. It may take a little experimentation to get the mud onto the front and to get it raked off properly, but it can be done, and it must be done. This is no time to cop an attitude. Stay with it.
Turn the straight-edge in different directions to get things on plane, and check the seat front with the level to get it plumb. When you are satisfied with the front, you can begin finishing the top of the bench.
Nothing in a shower is built level. All horizontal surfaces are tilted slightly toward the shower drain. This is so that none of the surfaces will collect and trap water. The shower seat should be tilted or sloped about a half inch from back to front.
As you finish the top, use your level in conjunction with a short straight-edge to accomplish the slope. At the same time, though, the bench top must finish up flat. You’re not building a ski chute here.
A shower bench should finish out at about the same height as a chair, which is 16 to 18 inches high. You will be adding the shower floor, so you might want to add mortar or a combination of mortar and block remnants to the top before you smooth it off.
When all the mortar has been applied, the bench should be allowed to set an hour or two. You can then go back and fine tune both the front and the top by scraping with a straight-edge or by slicing with the edge of a flat plastering trowel. Do not get the “it’s-good-enough-attitude” at this time. Stick with it until the seat is as perfect as you can make it. If you don’t, you’ll most certainly have the “wish-I-had-done-it-better-attitude” in the morning. This seat is going to become rock hard.
Tiling the seat is like tiling the shower walls. The courses of tile that go across the front of the bench should line up horizontally with the courses of tile on the shower walls. Everything should flow, in other words.
• John’s Famous and Secret Bench Top Trick
Often when I’m building a shower with a seat, I don’t finish the seat top until I’m in the midst of the tiling segment. I might, for example, find that a row of tile extends just beyond the top of the seat I’ve previously roughed in. Wouldn’t it look great if the seat finished out with a course of full tiles at its top?
I install the tiles, letting them extend above the top. After letting them set a couple hours or even overnight, I can come back with additional mortar and finish off the top of the seat. I use the top edge of the final course of tiles as a guide. You should spread thin set on the old mud before adding the new. The thin set will act as a bonder.
This bench doesn’t have full tiles at the top, but the secret method is being employed to increase its height. Guard this secret. It’s privileged information.
Guard this secret, too. Benches don’t have to be straight.