Thinset Over Painted Floor

The floor is a 4 inch poured concrete slab over an unheated utility room.

Thinset over painted floor.

It is applied to the substrate with a notched trowel. The painted surface has to be cleaned properly to ensure an adequate bond. Paint used on concrete will not bond with the tile adhesive. First a surface more textured and solid must be applied over the painted concrete.

Thinset tile mortar has a smooth slippery consistency similar to mud. Whether you have cracks chips or just a stained concrete slab thinset helps cover the old surface and create a new problem free area. Thinset is a mortar that is made of portland cement silica sand and moisture retaining agents. Mortar cannot be installed directly over painted concrete itself.

All paint will need to be removed before you begin installing the tile. This will seal the wood and create a matte finish that will adhere to the tile well and help to stabilize the. The house was built in the late fifties and the slab floor has been painted at least once. Only use epoxy and latex thin set products that state they can be used for bonding tile to paint.

Unfortunately the tile cannot be adhered directly to the painted surface. Apply a coat of sanding sealer or tile prep sealer to the floor with a paint roller. Thinset mortar is your default tile mortar for most indoor and outdoor applications. If the paint is not well attached then as the thin set adhesive dries and shrinks it might pull the paint loose.

A latex based thin set adhesive should be used over the latex based paint. This surface is called a scratch coat.