Sealing Grout

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Posted by: from Maple Ridge
9/24/2012 at 6:15:09 PM

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?

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John from JALS Corporation in Welland
Date/Time9/24/2012 at 7:05:32 PM

Did you apply the grout sealer after it dried?

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Date/Time9/24/2012 at 7:07:31 PM

In this particular case, the grout was allowed to dry for almost a full week, about 6 days I think.

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Date/Time9/24/2012 at 7:09:36 PM

He did NOT seal the grout nor the tile, should be sealed.

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Date/Time9/24/2012 at 7:17:34 PM

Well that's constructive...

The tile and grout sat for a week before we could get back in and seal it. Twice.

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Date/Time9/24/2012 at 7:50:33 PM

Seal it.


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Glen from BGS Projects in Lake Country
Date/Time9/24/2012 at 8:27:00 PM

May I ask what product you used for sealing? Also what base.


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Date/Time9/24/2012 at 8:32:14 PM

Grout is porous. Even after you seal it repeatedly it will still disclour when it gets wet. To truly seal the grout use epoxy grout.

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Date/Time9/24/2012 at 9:06:05 PM

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.

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Date/Time9/24/2012 at 9:36:45 PM

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.

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Syed Painting & Handyman Services in Brampton
Date/Time9/24/2012 at 11:07:43 PM

Sometimes this happen when the installers add extra water when mixing the grount to make the grouting easier. But could be other reasons too.

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Paul from Paul's Contracting in Barrie
Date/Time9/25/2012 at 5:50:43 AM

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!

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Nathan from Deglan Construction in Surrey
Date/Time10/2/2012 at 2:04:09 PM

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".

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