Is there any rhyme or reason why sometimes after grouting a floor or shower that when done the grout in some places will change colour and look wet again but only after it gets wet?
I have let the tile and thin set dry over the kerdi for days after, plus allowed the grout to cure for over a week and it still happens, not every time but about 1 out of ten times, which is still annoying.
Is there a fix for this or do you have to dig out the grout and replace it?
Sometimes when we show up for jobs such as this one, the client will purchase the products/supplies ahead of time, assuming they will get a better deal than I would offer I suspect. In this case the client purchased Mapei grout which I never use, (except for the plani patch for floors) and the sealer was a product I use often, Aqua Mix.
I have found that different suppliers make different claims but niot all preform well. Some go on nicely but crack or shrink and change colour. If the client buys their own, explain that you are just the installer and can't quarantee the results. And yes to the sealing, but make sure the grouting is done well before sealing.
Sometimes this happen when the installers add extra water when mixing the grount to make the grouting easier. But could be other reasons too.
Check colour batch codes to see if they're the same prior to beginning. If you have a few from different batches or manufacturing dates, dry-mix the bags together to ensure colour consistency. Measuring the water as per the directions for mixing helps ensure consistencies from batch to batch.
Control the amount of times grout is per-washed and keep sponge from being too wet. Excess water or even standing water during this step can sometimes also cause these issues.
Don't final buff tiles too early, the dust can fill the pours if grout is still moist and can cause discoloration later.
Hope these few tips help!
Ive seen this happen before. The fact that it happens 1 out of 10 ten times, It sounds like something called "Efflorescence".
Honestly its just unluckily picking a bag of grout up at a supplier that may have a slightly higher salt content than others. As the grout cures the salt is brought up to the surface with the water and can make some spots seem lighter than others in comparison.
It happens more often I find with greys and light blue grouts.
Id say go after brand name supplier. Although If you read the fine print on the grout bags.... basically most brands will basically say.... "Yep, sometimes efflorescence happens".
Search the TrustedPros directory and discover the best contractors in your area.Find your home service pro