Regrouting Decks and Showers
Let’s start our journey through regrouting decks and showers from a simple definition. Regrouting means – REPLACEMENT of existing grout. Sadly, one of the main reasons to perform regrouting is, if anyone else than a professional TILER already “regrouted” your tiles. Almost all “regrouting” jobs in Auckland are just a millimeter-thick finish over old grout. Such things are doomed to fail. It is not even possible to say, if the regrouting was necessary in the first place, as everything is covered with useless skin of new grout. In such an instance, REGROUNTING is the only option.
The photo on the left shows a classic example when rerouting is not necessary. It is important to understand that regrouting is NOT a cure, but just a cosmetic procedure. If the reason for grout failure remains unresolved, the new grout will fail (even epoxy). This reason and course of action can only be determined by a professional tiler, if one wants to avoid problems in the future. Explaining why, would take a full page of text.
Back to the picture, there is something else that is absolutely essential here, an EPOXY INJECTION to re-attach partially loose tiles. Only than the grout can be patched up, cleaned and colour-sealed. Although in such a small area a full re-grouting is actually less complicated (if that’s the only area).
Another good reason for regrouting is uneven grout surface. This again points towards a “specialist”. Either the grouting was sloppy or the water ratio in the grout mixture was incorrect. Too much water = weak grout. Now, “sloppy” can be overlooked (depending on how bad it really looks). The issue of weak grout, however, is a deal breaker. The painting of weak grout would be a waste of YOUR MONEY.
Efflorescence damage – a real reason to regrout
Yet another solid reason to perform regrouting is efflorescence. The efflorescence is caused by water collecting under the tiles and washing out salts (and flexible additives) from the tiling adhesive.
The “tiling over butynol” is the main sickness of decks in Auckland. The only adhesive that actually sticks to butynol (and a tile!) is also THE WORST adhesive for outdoor areas. It’s absolutely packed with latex and all sorts of other “goodies” which become the building blocks of efflorescence. The ordinary grout lets rain water through like a sponge. If the deck surface is uneven enough the rain water will collect under the tiles making efflorescence inevitable.
And more about decks. Let me tell you where you stand. The ONLY 100% sure method to get rid of efflorescence is to rip the deck apart, level it properly, install PROPER waterproofing membrane (suitable for tile installation), and tile it again… The cost? It would be somewhere in the “sweet Jesus!!!!” region. The only thing that can save you is regrouting with epoxy. The whole deal is to stop the rain water from getting under the tiles. – the problem solver
Epoxy grout – cheapest solution to efflorescence problem
The epoxy grout is 100% waterproof by it’s nature (but NOT efflorescence-proof). Yes, not a drop of water can pass (from the top down). Yet, if water gets under the tiles (somehow) it would start the vicious efflorescence circle again. The weak spots are always the junctions between the deck tiles and the building walls. Those spots are notoriously hard to get to, to even run a proper silicone lines. Besides, if the walls are covered with plaster (which soaks water just like ordinary grout) no silicone would help.
So, is the situation completely hopeless? Far from it actually. Keep in mind that your old grout was letting several liters of water under your tiles after every heavier rainfall. After the regrouting with epoxy is done, 99.9% of your deck area IS WATERPROOF. Yes, there will be weak spots which we cannot do anything about, but only a small fraction of rain water can pass through. Probably not enough to cause any problems before evaporating. The porosity of tiles is not an issue. Tiles can be sealed. This goes only for the most porous natural stone tiles or terracotta (which should be sealed in the first place anyhow).
HOWEVER! Since the main source of efflorescence remains (the tile adhesive), I cannot guarantee an efflorescence-free future. The regrouting of 30sqm deck would start from $1950 + gst. The re-tiling of the same deck would start fro $15K!!! It is not only about the installation of new waterproofing membrane and tiles. It is about installing the waterproofing membrane UNDER THE WALL CLADDING (at least 150mm high) and UNDER THE DOOR (usually range slider…). We’re talking a major renovation involving builders, not only tilers. I wouldn’t give 5min guarantee for waterproofing for anything less than that (nor would any self respecting TILER).
Do your homework…
The only choice you have is the amount of money you’re prepared to spend. What you would get from me is guarantee for structural integrity of epoxy grout (not for waterproofing as such or non-reapearance of efflorescence). Sounds “fishy”? I cannot imagine worse case scenario than ripping apart a perfectly good deck just because of a few spots of efflorescence. Now, THAT’S fishy! Listening to experts?
Every tiler will suggest tiling on top of existing tiles. Again! Consider the difference between “tilers” and tilers. Proper “tiling on top” should start from grinding the surface of existing tiles, than waterproofing the surface, than tiling, than grouting with epoxy to stay on the safe side. Can your deck handle the extra weight? How about the new level of tiles? Would it be almost equal with the level of the floor inside the room?
Every waterproofing expert will vote for ripping things apart and installing “a better” waterproofing membrane. He would be backed up by a builder who wants nothing more than to take out your doors and wall cladding.
Every grout restorer will tell you what I just did, plus he will know how to do the job in safest possible manner. The difference between professionals and “not so much professionals” still applies!
All I can suggest is, do your homework and listen to your own logic (specially when $15K is at stake). Have a look at the material data sheet of epoxy grout, dig more info on efflorescence. And whatever you do next, do NOT let non-tilers near your deck.