[Max Campbell]

We cleaned a slate floor that had been down about 7 or 8 years and never been sealed, then about a week later sealed it with Triple C's Stonetech - an impregnating solvent enhancing sealer that we have had some successful experience with. It looked great on the day.

Customer's asked us to have a look, because "white patches" have developed. We're expecting to find efflorescence, but could there be another cause, and why's it only doing it now? What can be done, apart from simply brushing it off?

[Tadgh O Shea]

Hi Max

Just wondering did you use a high alkaline based cleaner on the slate tiles to clean them first before you applied the sealer.

[Jason Smith]

This is quite a common problem, more often found with solvent based acrylic topical sealers.

One known cause is the product may have been applied too heavily or there are too many coats of sealer on the slate and moisture trapped underneath the sealer has caused it to lose adhesion from the tile.
Solvent-based sealers and damp surfaces do not mix, white marks will result if the sealant is exposed to moisture while it is drying, these marks are known as moisture blush or clouding.

To resolve the problem, the whole floor will need stripping right back or try applying toluene solvent diluted 1:1 with the sealer in the areas that have the white patches this can be a successful way of restoring the problem areas.

[Max Campbell]

Hi Max

Just wondering did you use a high alkaline based cleaner on the slate tiles to clean them first before you applied the sealer.

Moderately alkaline - I think pH 10 to 12 - described as "Heavy Duty" not " Very Heavy Duty" - Alltech's

[Max Campbell]

This is quite a common problem, more often found with solvent based acrylic topical sealers.

One known cause is the product may have been applied too heavily or there are too many coats of sealer on the slate and moisture trapped underneath the sealer has caused it to lose adhesion from the tile.
Solvent-based sealers and damp surfaces do not mix, white marks will result if the sealant is exposed to moisture while it is drying, these marks are known as moisture blush or clouding.

To resolve the problem, the whole floor will need stripping right back or try applying toluene solvent diluted 1:1 with the sealer in the areas that have the white patches this can be a successful way of restoring the problem areas.

It wasn't a topical sealer, and the floor had had no sealer previously. It was a single light (wiped off tile by tile) coat. It was about a week from washing to sealing. Thanks re the Toluene tip - where do I get some?

[terrazzoman]

i have a similar problem with a large area sealed with CCC products the only way is to remove the coating...its very similar to varnish
i totaly agree with jasons coments

[Jason Smith]

Alkaline cleaners tend not to disturb solvent based sealers, if you investigate further I think your find the consensus will definitely point to Damp or Moisture contamination.    

[Max Campbell]

its very similar to varnish

In what way? It's not a topical sealer - at least on porous surfaces it sinks in completely. I'm not doubting you, just looking for an explanation.

[Jason Smith]

Although it is more of a problem with topicals, solvent based colour enhancers contain a secondary polymer, sometimes acrylic to offer the enhancement. If they are not applied to completely dry surfaces or kept dry by the customer for up to 48 hrs you can incur problems with white blooming. I have to admit we have received this type of problem with our solvent based enhancer leading to us deleting it and formulating a water based product. There are a number of solvent based strippers out there that will resolve this issue, I would suggest going back to the manufacturer they will know more about there product and a product to resolve the issue than anyone else.

[Jason Smith]

Are you sure it isn't efflorescence Max?

Regarding the delayed timeline, we are not sure why it takes so long to appear? I've asked our chemist and investigated the situation without an exact answer. If its going to show it normally appears quite quickly but I have heard the odd occasion where the problem shows after a few years and it hasn't been a efflorescence problem.

It's a very frustrating one I've had experience off myself.

[Jamie Pearson]

I rectified a slate sealed with an own branded version of the CCC product.

White spots all over the floor. The only thing we can think it was is sweat from either the applicators gloves or brow during the application.

We stripped back the individual tiles that were affected then put one more coat on the whole floor to blend.

[Jason Smith]

I rectified a slate sealed with an own branded version of the CCC product.

White spots all over the floor. The only thing we can think it was is sweat from either the applicators gloves or brow during the application.

We stripped back the individual tiles that were affected then put one more coat on the whole floor to blend.

I can relate to that, years back when I was restoring floors a co-worker walked across the floor in stocking feet after we sealed a floor, the same thing showed up the following morning. We knew that was the problem because it was in a walk way equally spaced in foot steps.

[Jason Smith]

This is quite a common problem, more often found with solvent based acrylic topical sealers.

One known cause is the product may have been applied too heavily or there are too many coats of sealer on the slate and moisture trapped underneath the sealer has caused it to lose adhesion from the tile.
Solvent-based sealers and damp surfaces do not mix, white marks will result if the sealant is exposed to moisture while it is drying, these marks are known as moisture blush or clouding.

To resolve the problem, the whole floor will need stripping right back or try applying toluene solvent diluted 1:1 with the sealer in the areas that have the white patches this can be a successful way of restoring the problem areas.

It wasn't a topical sealer, and the floor had had no sealer previously. It was a single light (wiped off tile by tile) coat. It was about a week from washing to sealing. Thanks re the Toluene tip - where do I get some?

I think you, should be able to buy small amounts from eBay or Screwfix?

[Max Campbell]

Thanks for all the thought put in so far. We haven't seen the "white patches" yet, and I am hoping for efflorescence, but want to be prepared. We will get in touch with triple C - who to give them their due have been very helpful with advice in the past - but wanted a broader advice base.

The thought that we could deal with the individual tiles is hopeful.

Thanks for the toluene tip, Jason

[Jason Smith]

Pleasure Max, good luck with it... Let us know what comes of it, always interested in results and new solutions to issues.

[Kev Martin]

We cleaned a slate floor that had been down about 7 or 8 years and never been sealed, then about a week later sealed it with Triple C's Stonetech - an impregnating solvent enhancing sealer that we have had some successful experience with. It looked great on the day.

Customer's asked us to have a look, because "white patches" have developed. We're expecting to find efflorescence, but could there be another cause, and why's it only doing it now? What can be done, apart from simply brushing it off?

Max

Whenever we apply an Enhancing Impregnating Sealer we are absolutely anal in the application process. 

The sealer we use in this process is called Aqua Mix Enrich N Seal and unlike any other sealer it uses itself as a transport system where as other brands either use solvents or water.  The end result is no matter how well you clean off there is always a risk that there will be some sealer left on the surface.  We clean off after application using paper towel in the first instance and then we buff over again using either terry towels or Microfibre Terry Cloths.  However, even after all this two things can happen, either some of the sealer comes back to the surface because the stone is so full it can reject it, or the sealer was not totally cleaned off 100% and you can get footprints or similar.  To combat this we usually take a white pad on a rotary and using some pH Neutral cleaner we go over the whole floor again and vac up.  This we find sorts the problem.

Kev Martin
Marblelife Ltd
Tiling Logistics

[oliver campbell]

Hi I'm Max's son and business partner! (the guy that started this thread)

We went to see the floor to day and have some pics...

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[oliver campbell]

[oliver campbell]

[oliver campbell]

sorry pics came out so big... its a real pain trying to up load them to a topic!

also worth noting, the white patches wernt there a few days after sealing and only came up a week or so later and its at a time. I think it is eflorecence, if so is there anything we can do, anything...