When figuring out how to install bathroom tile, the color and texture is important to consider because it’s such a major component of any bathroom. But for the tile to be permanent, it has to be installed on the walls and on the floor in a way that will last. Too often, people who are either homeowners or average contractors don’t take the care that’s needed to see that tiles are mounted correctly. As a result, I have seen the most beautiful tiles in the world flop loose in a matter of months because they’re not properly attached. These end up clattering around as people step on them along the floor, and allow water to leak when attached to shower and tub surrounds. This won’t happen, however, if you follow some important steps.
The key to permanence in tiling lies not so much in the kind of tiles you buy; any tile, by its very definition, will likely endure for the life of your home. Instead, success depends upon what lies underneath the tiles. In this case, the rules are simple: never mount tiles directly to wood, and never mount them directly to plaster or drywall. Although I’m a big fan of wood, it is a resilient material that moves back and forth when stepped on; tiles that are set directly onto it will eventually work loose. Drywall and plaster present another problem: though perfectly adequate surfaces for a wall, these do not stand up well to moisture. Tile an ordinary sheet of drywall in a shower surround, and within a few short months it will turn to a damp mash.
Let’s look at floors first, to see how they should be handled. In the past, tile floors were set in a thick, cement-based material called mudset. Many shower basins are still created this way, and it involves pouring a sand-and-cement mixture about two inches thick, to create a solid, immobile base for the tiles that follow. To accommodate the thickness of the mudset floors, the other floors in the house had to be carefully calibrated in terms of height so that they would all match up. Except for the shower stall, this is an extravagant method that is rarely used today, although you will no doubt find remnants during a gut renovation of an old bathroom. Instead, there is a much better and cheaper method now available.
The solution for how to install bathroom tile today lies in concrete backer board (also known as cement board), which is sold under brand names such as Durarock, Wonder Board, HardiBacker, and PermaBase. This is similar to ordinary drywall used in walls and ceilings, with some important differences. For one thing, it’s made of solid concrete that’s held together with a Fiberglas mesh. The beauty of concrete for a bathroom lies in the fact that it withstands moisture, almost to a fault. In fact, I could take a piece of concrete board, throw it into Lake Michigan, and come back a month later and it would still have maintained its structural integrity. Ordinary drywall, by contrast, would turn to pulp within an hour.
In addition, concrete expands and contracts only minimally compared to other materials, and are extremely stable as a result. Even as the wooden sub-floor expands and contracts, the concrete board won’t move, which means the tiles and grout will remain free of cracks. Under normal use in the bathroom, the concrete board will endure, even if the grout joint between the tiles cracks for some reason, or if the tiles begin to pull loose because they weren’t correctly installed. Concrete board comes in smaller sheets than drywall, with an average size of 3 by 5 feet, rather than 4 by 8 feet. This makes them easier to lift because, after all, they’re solid concrete.
Installation of the concrete board requires great care, especially in how it is screwed into place. Rustproof screws, rather than nails, are essential; in addition, they have to be placed in a specific pattern rather than simply screwed in at random. For the floor, the screws should be placed every six inches around the perimeter of the room. Then, in the remaining area they should be screwed in place at regular intervals between 10 and 12 inches apart. You can get away with using fewer screws, but there is no guarantee the concrete board will be firmly attached to the sub-floor, and you may see cracks form in the file floor as a result. Pay attention as well to how the screws are driven into the board. They need to be countersunk, which means that the head of the screw lies below the surface of the board. There’s literally a slight depression where the screw lies, so that if you drag a putty knife across the floor, it won’t hit a single screw head. This will prevent the screws from popping up over time once the floor is finished, which could easily break or loosen the tile that is laid over it.
For installing bathroom tile on the walls, the task is somewhat simpler, since there is no sub-floor involved. Instead, the concrete board is screwed directly to the wall framing, which is called the studs. You should install the screws every 6 inches along the edge of the material, and 8 inches in the field, or the center, of the board to ensure a solid hold. The important part here is to make sure the edges of the board are screwed directly into the studs, even if this means cutting the concrete board into thin strips. This is the only way to guarantee a solid hold.
While we’re on the subject of cutting, let’s discuss the best methods. An ordinary utility knife, which is the implement of choice for cutting drywall, works with concrete board, but the blade takes a beating. The object here is to score a line with the blade, then snap the concrete board along that line. A better method is to affix a small masonry blade to a circular saw and do the job that way. It creates a great deal of dust, but the cut comes out smoother and quicker. You are also less likely to waste concrete board that crumbles instead of snaps just where you want it to.
This article on installing bathroom tile was supplied to us by “Plato” from the DigitalPoint forums under a private label rights license.