Can You Put Tile Over Tile?

When is tile over tile a good idea?

Tile over tile works when the existing tile is flat, completely bonded (no hollow-sounding tiles), and your floor structure can handle roughly 6 to 8 pounds per square foot of additional weight. The bathroom is the most common place this works since the tile is usually intact and the room is small. Stay away from this method on second-floor wood-framed rooms unless an engineer confirms the framing can handle the load. Slab floors handle the weight without issue.

How do you prep existing tile for new tile?

Clean the existing tile thoroughly with a degreaser to remove soap scum, grease, and old wax. Scuff or score the glossy surface with 60 grit sandpaper or a tile scoring tool to break the smooth glaze and give the mortar something to grip. Replace any loose or cracked tiles in the existing floor first since those will fail again under the new tile. Apply a bonding primer like Mapei Eco Prim Grip if you want extra grip insurance, especially on porcelain.

What about the height issue?

Tile over tile adds at least three-eighths to one-half inch of height when you account for thin-set mortar plus the new tile. That changes the floor level at doorways, transitions to other rooms, and toilet bases. Door bottoms may need trimming. Toilet flanges may need extender rings. Cabinets and dishwashers may not slide back into place. Measure all these clearances before committing to the project. In a bathroom, the toilet flange height is the most commonly overlooked issue.

When should you remove the old tile instead?

Remove the existing tile if it has loose pieces, deep cracks, water damage underneath, or if more than 10 percent of the tiles sound hollow when tapped. Also remove if you cannot afford the added height, if the floor structure cannot support the weight, or if the existing grout has multiple failures. Removal is more work but gives you a fresh start with no risk of bond failure from the layer underneath.