Thoroseal to seal my pond, many cracks after draining?

g20zoomMay 26, 2014

Hi, my contractor is drying to restore our 100 gallon concrete block fountain/pond and is failing.

First, he sealed it with thoroseal only(no acryl60). It dried...and I noticed many spider cracks on the vertical surfaces only. The cracks were hairline

second, he recoated thoroseal only...this time wetting the surface first. it dried, no more cracks!

4-5 days later, I filled with water upon finding no cracks...seemed to hold fine, but i drained it 4-5 later to clean it out.

upon draining it, I noticed tons of hairline cracks again.

any ideas?? Is it because they are not using Acryl 60? or are they mixing the stuff wrong. maybe not letting the thoroseal stiffen up 30 minutes before applying?
I'm confused...I'm sure the workers are not reading the instructions...


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waterbug_guy(Phoenix AZ (Melrose))

There are many ways this type of thing can be messed up, many. The Acryl 60 isn't strictly required, but does provide some insurance should other things not be right. For example, if the coating wasn't kept damp the risk of shrinkage cracks increases when Acryl 60 isn't used. Doesn't mean it will crack, just that risk increases. Being in the sun would increase risk more. Low humidity increases risk. So the manufacturer says to use Acryl 60 because they know many people will cut corners.

From your description sounds like you have shrinkage cracks, but I'm not there so don't know.

Down the road the Acryl 60 could also keep the coating stuck to the concrete. Without it the risk of delaminating increases. Thorseal by itself can certainly bond to concrete and stay bonded for many years if a lot of steps aren't skipped like very good cleaning, damp concrete, right temp, not too much or too little water added to the mix, it's applied in a timely manner, it was given some time to sit after mixing, not using clean water, etc., etc., etc. Acryl 60 helps a little to reduce risk of sloppy work.

You don't say you have a leak, so, not sure if you're looking for problems. The bottom line imo with contractors is they're paid to get a result. How they get the result is up to them. Defining what the result should be and how it's measured is up to the person writing the check.

    Bookmark   May 26, 2014 at 6:18AM
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