When a hard floor needs resealing, not cleaning

The water test

Put a few drops of water on the floor in a spot that gets walked on and leave them two minutes. If they sit as beads, the seal is intact and a clean will bring the floor back. If they soak in and darken the stone or grout, the seal has gone and the floor is drinking whatever lands on it.

Do the same test in a corner nothing walks on. If the corner beads and the walkway soaks, the seal has worn through in traffic rather than failed everywhere, which is the usual case.

Why cleaning an unsealed floor backfires

A clean opens the pores of the stone and lifts out everything sitting in them, which is the point. On a sealed floor that is the end of it. On an unsealed one you have just given a porous surface a fresh start at absorbing the next spill, and it will mark faster than it did before.

That is why we test first and say so, rather than clean it, take the money and let you find out in March.

What each costs

Cleaning starts at £60 for a kitchen or bathroom floor, £90 for a hallway and kitchen together, £75 for a conservatory and £150 for a whole ground floor.

Sealing is quoted separately because it depends entirely on the stone: a glazed porcelain does not need it at all, a honed limestone wants a penetrating sealer, and a quarry tile wants something different again. We will tell you which you have.

How often

• Glazed porcelain or ceramic: never seals, only the grout does.
• Natural stone in a kitchen or hall: every two to three years.
• Grout on any floor: every two years, sooner if it is light-coloured.
• Anywhere a dog comes in wet: check it annually with the water test.