Backer board is the best substrate for tile. Plywood and OSB substrates can warp and mold with water damage, but tile backer board will do neither. Here, we look at tile backer board, including types, applications, and tips for properly installing it. Backer board comes in a variety of materials for a range of purposes. These are the most commonly used tile substrates :. Made of cement and reinforced on the top and bottom with fiberglass, this waterproof backer board is generally used for tiled shower surrounds and floors in wet areas.
It can also be used for exterior tiling jobs. Fiber cement board, also known as fiber board, is made from a sheet of Portland cement mixed with sand and cellulose fibers. Fiber board is recommended for floor tile installations, since thin-set mortar adheres well to it, ensuring a strong tile-to-floor bond. Made from water-resistant gypsum treated with silicone, glass mat gypsum board is reinforced with fiberglass mats on top and bottom.
This type of backer board is lighter than cement board and is ideal for damp spaces like the tub surround in the bathroom, although it can become damaged if water gets behind it. While not considered backer board, water-resistant drywall can be used in spaces where occasional splashes may occur but which are otherwise dry, such as a glass-tile backsplash in the kitchen.
Alternatively, instead of backer board, you can use two layers of plywood topped with a waterproof uncoupling membrane, which is a lightweight plastic underlayment that allows independent movement between the tile and the plywood to prevent cracks in the tiles and grout. Backer board is usually a simpler way to go than plywood. Laying tile directly on a surface like plywood or an existing floor can cause major problems down the road.
Tile installed directly over wood will likely buckle as it absorbs moisture, and the wood will be susceptible to mold and mildew. Additionally, wood substrates expand and contract with temperature and humidity changes, which makes it an unsuitable surface for tile. Tile laid directly over an old linoleum or vinyl floor may shift and break if the surface contains air pockets or is susceptible to moisture. Laying tile directly on an existing floor can also cause problems if the tile is very heavy or will be supporting heavy furniture.
Half-inch cement backer board is ideal for most tiling jobs, including walls, floors, countertops, and ceilings. You can cut cement and gypsum backer board with a jigsaw fitted with a carbide blade.
Press the backer board firmly into the to mortar, then screw it to the sub-surface, placing screws around six to eight inches apart. Use screws specifically designed for your type of backer board, as recommended by the manufacturer.
Sink the screw heads slightly below the surface of the backer board. When all of the boards are installed, fill the joints with thin-set, and smooth them with the flat side of the trowel so that the thin-set extends a couple of inches on either side of the joint. Choose a sheet thicknesses based on the application:. You will need to cut your cement board to various sizes to suit your project, and knowing how before you start your project can keep you from making costly errors.
You can cut the cement board with a utility knife and a T-square. Score the cement board deeply with two or three passes with the knife, using the square to ensure a straight line, then snap the waste area of the sheet back to break the board along the cutting line. Cut the fiberglass mesh along the backside of the board, as applicable, to complete the cut. To make round or curved cuts, use a jigsaw with a carbide blade or a drill and a hole saw bit.
Make a rough plan for the cement board sheet layout, based on the area to be covered and the size of the cement board sheets. The joints between the sheets should be offset by the joints in the plywood or other subflooring by at least 8 inches, for maximum floor stiffness.
If necessary, plan to start the first row of sheets with a partial sheet to create the offset. Mix a small batch of thin-set mortar as directed by the manufacturer, mixing the dry powder with water in a bucket. Cover an area just large enough for the first cement board sheet. Place the first sheet over the mortar bed.
The rough or embossed surface of the sheet should face up, as applicable. Fasten the sheet with cement board screws, using a drill-driver, making sure the screws are flush with the surface of the sheet or are slightly recessed.
Space the screws 8 inches apart across the entire sheet. Use only cement board screws and alkali-resistant cement board joint tape. Standard screws and drywall joint tape will corrode or deteriorate from contact with cement board. Continue installing sheets to cover the entire area. Mix fresh mortar only as it's needed to prevent it from drying before you can use it up.
Apply cement board joint tape to all of the joints between sheets, adhering the tape with its self-adhesive backing. Mix more thin-set mortar and, using a drywall knife, cover the taped joints with a thin layer, much as you would do when mudding drywall joints. Tool the mortar with the knife so the tape is covered and the joints are flat and smooth.
Allow the mortar to cure completely, following the manufacturer's recommended drying time. Installing cement board on countertops is very similar to the process used on floors, but countertops usually need an additional strip of cement board along the exposed edge of the countertop.
This creates the built-up edge for securing bull-nose or other forms of edge tile. Cement board on walls also uses the same techniques, but in this case, there is no layer of mortar behind the cement board as it is screwed directly into the wall studs. Consult the cement board manufacturer for recommendations on using a moisture barrier between the board and the wall studs. This may be thick plastic sheeting or another type of water-resistant membrane. Actively scan device characteristics for identification.
0コメント