Concrete effloresence

[1949 caddyman]

I have a covered concrete patio slab that was 20 years old that we had covered with a textured cool deck product. It was then painted using acrylic paint. All was good for 2 years and then the texture started lifting due to effloresence. After it rains a fine white powder forms in the area of the delamination.
The company that put it down repaired one spot under warantee but that lifted after 6 mo. and now all around the outer edge the same problem is happening. The slab had no vapor barrier under it. Is there any thing that can be done to help the texture to stick to the slab?

 

[dcs Inc]

What was the product? (A Lot of products can be made to look like cool deck). Most often delamination is caused by improper prep of the original concrete, improper installation or just a crappy product. The type of polymers used will tell the tale. PVA's will actually rewet if water gets under the sealer. Acrylics get brittle and loose their elasticity. Styrenes are, well... just ****. A lot of companies are using acrylics because they are cheap but are not user friendly. The poly vinyls, (pva's) rewet which may be your case.

If in fact an acrylic paint was used on top of the overlay, this may cause moisture to become trapped in the overlay itself because most paints are not breathable, thus why paint is horrible to use on concrete. Most overlays allow moisture transfer and are breathable. Stop the moisture, start the delamination. As far as a fix, you need to find a topical binder product. (this is after prepping the surface) Usually an acid etch and neutralize wash and you are ready to apply the binder, then overlay. If there is a bond breaker on the concrete surface(acid doesn't fizz) You have to grind the surface. that's the short list.
gene... elite crete Indiana

 

[Edger]

In my experience efflorescence is normally caused by water migrating up through the slab which would explain why you have lifting. It can also migrate from the sides of the slab, but then the efflorescence would only be concentrated around the edges of the slab.

Two products are guaranteed to stop it quickly, but you will have to grind off the existing product to ensure penetration.

Ring http://www.protecrete.com/index.html and see what they recommend or the other one is http://www.aquron.com/our-products/concrete-protection-and-waterproofing/aquron-cpt-2000/.

Once you have waterproofed you should be able to apply any product normally without moisture problems in the future.

 

[1949 caddyman]

The efflorescence is around the edge of the slab. Have you used the protecrete product?

 

[Edger]

Haven't used Protecrete although it is used extensively in Australia, but I have used Aquron 2000 many times and found it great for the job. Sounds like the water is not coming from underneath, but rather from the outer edges. The Aquron can be sprayed all over or just the outer 6 inches and it will penetrate through to stop the water migration. Here is one Australian distributor http://www.con-treat.com.au/waterproofers.php

 

[1949 caddyman]

The slab has a plastic deck drain along the 30' length with another slab abutting it so its not possible to seal that outter edge. I can seal the 10' end edge. From what I have read on the web sites I would have to remove all old top coating. Could I just remove loose coating, seal with these products and then recoat just those areas or would the efflorescence just spread to the unsealed areas?

 

[LegacyIndustrial]

Our HD39 should do a similar job for you.
Definitely, less than an Australian boat or plane trip.

 

[Edger]

The Aussie guy was just an example of their widespread business, Aquron and Protocrete are USA companies. Besides, a trip down here would be great, got most of the world's ten deadliest snakes, biggest reptile (saltwater crocs), great whites, redback and funnel web spiders. Something for everyone on land or in the water - just kidding.

With Aquron you should be able to just grind about 6 inches around the edges and apply, it will waterproof down to seal the edges from the top. See if you can get a contractor to do that for a reasonable price because I think Aquron only sell through applicators.

 

[LegacyIndustrial]

Edger:

I will be making that trip. I'll look you up when I do.

 

[Edger]

Definitely do that.