Not completely sure about this one, it is worth trying to eliminate grout haze as you say. I must just say that I am amazed at the number of people who talk about using vinegar and water – I know it can be a good thing to use ‘home remedies’ and it seems to be very fashionable, especially on the US side of the pond but I think it is ‘bad advice’ – often given out by tv programmes and other web sites. The reason I don’t favour it is that it contains an acid (acetic) – admittedly in very small quantities but more than enough to do permanent damage to acid sensitive surfaces such as pigmented grout, and any calcium based stone. Not an issue here in your case but on the other hand, where an acid is required (and safe to use, like on porcelain) it is nowhere near strong enough.

So, to eliminate the grout haze try some proprietary grout haze acid cleaner, based on phosphoric acid or equivalent (on no account use muriatic or hydrochloric). If it is a polymer modified grout, you may also need to use a solvent type cleaner – I have covered this else where so won’t repeat now.

Ok, if you eliminate grout haze as the problem, what else could it be? – Well it could actually be a manufacturing fault. Without seeing pictures or knowing more about the tile it is hard to advise, it could be as simple as different batches. You don’t say if the tiles are supposed to be textured or smooth, I am assuming that they are supposed to be textured, and it is the shiny ones that are out of place? This, if it is the case, it very odd, it could be something as simple as the wrong tiles mixed up with yours but unlikely. Any chance you could post some pictures – or send them to me by email?

bit of a ‘how long is a piece of string’ question but you are absolutely correct, no sealer can last indefinitely. As you have not told me what type of sealer or anything about the type of stone, you cleaning regime etc. I can only make vague generalizations but here goes.

There are two broad types of sealer: coating and impregnating. Coating sealers are visible coatings, often with some degree of intentional shine or finish. They are on top of the stone and so will be subject to wear – all that foot traffic you mention. They are also more prone to the effects of strong cleaners.

most coating sealers can last anywhere between 3 to 6 months for the ‘lesser’ quality ones and 6 months to 3 years for the better ones
Impregnators, as the are below the surface, do not suffer from wear in quite the same way and as a result, some can last upwards of 15 years or even longer.

The things to bear in mind, if you have a high foot traffic and the stone is cleaned aggressively with strong alkaline cleaners/bleaches – your sealer will not last anywhere near its potential life expectancy – in some cases a coating sealer may be stripped straight back off again, while Impregnators will rapidly degrade under such circumstances.

One more thing to consider is the stone itself; a soft stone or tile like some limestones and terracotta will wear comparably fast themselves, and as they wear, they take the sealer with them.

There are lots of things you can do to prolong the life of your sealer, like reducing the amount of grit that gets onto the floor with dust mats, and use neutral cleaners for regular washing. But I would suggest that for Impregnators you do a water test once a year (see article above)- as soon as you detect a deterioration, in the sealer, you can usually top it up with another coat. Coating sealers are rather easier to see as they loose their ‘finish’ so there are visible signs.

Hope that helps, sorry it was so late

Ian