Polished porcelain : as its actually a piece of clay fired and polished - can benefit from sealing as it has pores
Glazed porcelain : has a glaze applied to the surface to fix on the pattern : the glaze covers the pores so it can't absorb and shouldn't need sealing
Imitation stone porcelain : can be glazed or unglazed generally the rough stuff is unglazed : will benefit from sealing
Ceramic tiles : As we know them range from white to any colour and don't get polished as the biscuit is not hard enough : to fix the colour and or shine these tiles must be glazed : glazing closes the surface thus the tiles do not need sealing.
Quarry tiles : basically super baked clay like the old engineering bricks : generally don’t stain but mark and were given a coat of linseed to give them some protection and sheen : have seen cheap ones take grout colour and anyone selling sealer will try sell you a topical one : can or can't be
tiler
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