Tile – Laying new tile on subfloor with old plumbing holes, patch needed

subfloortile

Laying floor on a subfloor that has old plumbing holes in 3 places. The biggest one is just 2 inches, the rest are smaller. Otherwise the floor is in excellent condition.

I'm using ditra. Is it necessary to cover up the holes to lay the new tile floor on top. I'm using small porcelain tiles on a mesh matrix.

If it is necessary to cover the holes, would a thin piece of wood veneer do?

Best Answer

Someone will eventually put weight on that point. You want it properly supported. Cut out the piece of subfloor containing the holes and patch a new chunk in such that force is properly transferred to floor joists.

Doing it right the first time is a LOT easier than fixing it later.