What Is The Best Sealer To Seal My Porcelain Floor Tiles?

What is the best sealer to seal my porcelain floor tiles is one of the most frequently asked questions I hear. The answer can depend on the finish of the porcelain; for example, it could be a standard, smooth finish, it could be slightly textured (like a faux slate) or heavily textured, perhaps for anti-slip purposes. However, by far the most common question I receive is in relation to ‘polished’ porcelain.

There are still some high-quality porcelain tiles out there that do not require sealing. If you are lucky enough to have one of those then you are not going to need to do too much to keep it clean and looking good. Unfortunately, more and more of the porcelain sold here is of a somewhat more unpredictable quality, at least in terms of porosity and susceptibility to sub-surface staining. If you suspect that your porcelain might need sealing there are couple of ways you can check:

1. Do a water drop test – put some water on the tile and leave it for about 20 minutes then wipe off. If there is any darkening of the surface, showing that some water has penetrated the tile, then it will benefit from being sealed.
2. You can do the same thing with oils (warm engine oil off your car’s dipstick, cooking oil etc)
3. Or, for the ultimate test, use a highly penetrative chemical like a solvent; a permanent ink marker pen is perfect – needles to say, do this test on a spare off-cut, not on your floor!

Having determined that your porcelain needs sealing, which sealer should you use? First of all, the ‘type’ of sealer you will need is known as an ‘impregnating sealer’, as the name implies, it is a sealer that penetrates the tile and lies just below the surface, acting like a safety net to contain contaminants and keep them at the surface until they can be cleaned.

There are many impregnators out there and the old adage of “you get what you pay for” is certainly applicable here. Next question is what is best, solvent-based or water-based? Well this is one of the very few situations nowadays where I would still favour a solvent based one, not because water based is not up to the job, quite the contrary,  some modern water-based sealers can out-perform the best solvents, but simply because porcelain has a very dense surface and a solvent-based impregnator will penetrate it more easily.

So, having decided that a solvent based sealer is required, ideally we are looking for a high performance one that is as kind to the user and the environment as a solvent sealer can be, so check the labels, there are some better products available these days with less pungent odours than in days gone by. However make sure work with plenty of ventilation..

What if I want to use a water-based sealer? – No problem, you can, go for a premium water based sealer; just adapt the application a little: allow a liberal quantity of the sealer to dwell on the surface for a little longer. Then rub in the sealer with absorbent cotton or paper towels, leaving the surface of the tiles dry and free of sealer residue as per normal.

Is there anyway of darkening the porcelain? – This question sometimes arises, in particular with polished black porcelain. In some cases, solvent-based impregnators do darken the tile, but only marginally. There are some enhancing sealer s that can do a very good job, provided they can get into the porcelain, I have had some success with Enhance ‘N’ Seal on black polished porcelain, making a slightly greyed-out looking tile pure black. It won’t work on every tile, so you will need to be prepared to test, and it is expensive, but you will not need much of it as it goes such a long way.

I will come back to this topic later and discuss how to pre-seal a textured porcelain to aid the grouting process.

Copyright Ian Taylor and The Tile and Stone Blog.co.uk, 2013. See copyright notice above.