QUESTIONI have unglazed porcelain tile that flows from the inside of the home to a large patio outside, 18”X34” tiles. The installation is about 18 months old. The grout and tile was sealed after installation, inside and out. I had a small repair on the patio tile. The installer suggested I reseal the patio grout and tile. Do I need to do this? It was going to be several thousand dollars. If need I’d prefer to do it myself
ANSWERANSWER - The unglazed porcelain tile should technically be impervious with an absorption of 0.5% or less. That doesn't mean it can't stain, when it can if something is left on it long enough and not cleaned up timely or properly.
Sealers are not permanent. They do wear depending on what they have been subjected to in terms of the environment and how they have been used. Generally speaking you have to re-seal every year more or less. The rule of thumb is that it a drop of water doesn't bead up tightly then it needs to be resealed.
Before resealing the tile and grout have to be clean and dry. You should use a penetrating sealer on a porcelain tile. Apply the sealer with a hand spray bottle and rub in with a lint-free cloth. Then immediately buff dry the tile surface with a dry lint free cloth. If you leave excess sealer on the surface it will get sticky and create a cleaning problem.