Thin Brick Wall Preparation

Clean Masonry

• Masonry walls require little preparation, whether inside or out. Thin bricks will adhere with mortar to poured concrete, concrete block, stone or other masonry surface. Thin brick bonds with the wall masonry and becomes part of the wall. Preparation requires cleaning the wall, removing any nails or other impediments, and patching any holes or cracks.

Moisture Barrier

• Exterior walls require preparation for thin bricks. The first step is a moisture barrier. Some type of waterproofing membrane must be fastened to a wood-sheathed wall, typically with staples and a construction stapler. The waterproofing must cover the entire surface. Metal flashing must be installed around windows, doors and any edges to seal them.

Metal Lath

• The next step for exterior walls is putting on metal lath, nailed through the sheathing to studs in the walls. Seams should be overlapped so the entire wall is covered completely. A "weep screed" of metal flashing with holes in it should be fastened to the bottom of the lath, so any water that gets behind the thin brick will drain out and not create problems.

Mortar "Scratch" Coat

• Final preparation for an exterior wall is a "scratch" coat of mortar, applied with a trowel over the lath about 1/8-inch thick. It should be put on as evenly as possible and completely cover the lath. As it begins to set, scratch the surface horizontally with a notched trowel, a stiff bristle broom or a leaf rake to provide a rough surface for thin brick mortar to penetrate.

Interior Walls

• Interior walls with drywall should be covered with thin plywood or cement fiber backer board before thin bricks are installed. Either covering can be nailed to studs through the drywall. Extremely smooth material should be rough sanded to create texture for adhesive to bond to. Once the wall is completely covered with a suitable base, thin bricks can be applied with tile mastic.