Ceramic Tile Over Mastic

Does not fill gaps in a substrate or have building characteristics as it is more watery than thinset.

Ceramic tile over mastic.

It avoids the time consuming messy tear out process. Remove any cracked broken or loose tiles with a hammer and chisel and replace them with new tile. You can lay new ceramic tile right over the old using the prep techniques we show here. To replace a broken tile butter the back of a new tile with mastic and press it securely.

Mastic is an organic glue made from the sticky resin of the mastic tree. Best used for tiles in the 8 inch range or smaller. Grind them down with a grinder. Not recommended for tiles over 15 inches.

Should the tile get wet the mastic may soften negatively affecting the bond of the tile to the substrate. Mastic adhesive is very sticky making it well suited for vertical applications where tile may slide. Tiling over an uneven surface will give you less than stellar results so level out any globs of dried grout with a sander and secure loose tiles with fresh tile adhesive before beginning the project. If you do decide to remove it yourself i found that the best way to remove.

The adhesive often called carpet mastic used under most glue down carpet is usually water soluble and tends to prevent thinset from properly adhering. Lay a level on the old tile and mark any high spots. I don t want to go further till i know what i need to do to the mastic it s a very thin coat as if applied with a brush or roller it s not at all lumpy. Contractors we have spoken to think the best approach is to put down new ceramic or porcelain tiles right over the existing adhesive.

Roughen the tile with 80 grit sandpaper. I began using the 447 primer over the mastic and that helped some. Press the tile onto the floor. When the building was converted to residential the developer removed the vinyl tiles and just carpeted over the mastic.

They said capping the mastic in a seal coat or thin layer of concrete wouldn t be a good idea they d need to pour rather a lot of concrete for that. It s available as a thin liquid thick glue or a sticky paste.