The most common way to create faux brick is to use a sponge to create bricklike texture on an existing wall that has been painted gray or some other color that represents the mortar between the bricks. The fastest way to do this is to cut a household sponge to the size and shape of the bricks you want, then use it as a stamp to create each brick individually. This is quick and easy, but the least realistic way to create bricks. For a slightly slower--but better looking--technique, use masking tape to tape out your "mortar" lines between bricks on your painted wall, then use the same type of sponge to dab paint on over the tape for your bricks. Blending three similar colors, such as a deep red, a rusty orange and a dark maroon, helps give your bricks a more realistic look. Dab them all on at random with the same sponge and blend them by dabbing with a clean sponge. Never wipe or smudge the colors, as it will remove the sponge texture, which is what gives the bricklike look.
Give your bricks more dimension and a physical texture--rather than the visual texture of the sponge--by adding something to your paint. For temporary applications, such as theater sets, mix sawdust and white glue into your paint to get a rough brick texture, then sponge it on over taped mortar; make sure to remove the tape before the paint dries. For particularly heavy textures, simply spread on the thickened paint and wipe away the mortar lines with a finger instead of taping them. Color can be painted on later. For household use, an approved fireproof substance must be used to give the paint texture. Granular wall texture is sold at many home improvement stores; simply mix it into the paint according to the manufacturer's instructions, then adjust the amount of texture to get the type of brick you want and spread or sponge it onto your wall.
To create a full false brick wall, such as for a child's playhouse, stage set or party decoration, cut your walls out of foam insulation sheets (the pink kind sold in home improvement stores works best). Seal the foam with a few coats of white glue, then paint on your bricks using a sponge or physical texture technique. If you are creating party decor, consider cutting the side or top edges of the foam with a jagged line that follows the brick pattern, as if the wall was taken out from a larger wall and bricks are missing.