seal a concrete water tank

timbo · 01-10-2007, 03:53 AM

have built a concrete water tank, sprayed 32mpa concrete , with y20 reo,internal has a rough finish .need to seal or render it,is a mix of sand and cement enough,trowelled on steel finish

Bonus · 01-10-2007, 01:23 PM

Look up a product called "Xypex". It's a cementitious compound that you apply to the surface that bonds with the conc. and, as I understand it, makes micro-crystals that don't let water through. When I built a conc. cistern, I had the conc. co. mix it in to the batch.

Ts will know the REAL answer if he shows up.

timbo · 01-10-2007, 07:27 PM

thank you will do a search on it

tkle · 01-10-2007, 07:42 PM

Thoroseal,Superblockade to name a couple more.No difference between white or grey except color and cost.Follow instructions exactly.Two coats'll do it but 3 or 4 is better.

concretemasonry · 01-10-2007, 09:23 PM

I don't know about Superblockade, but Thoroseal has been around as long as I can remember and I am 66. The complete Thoro line has been used for yesrs on commercial, residential, industrial and civil(dams) repair, waterproofing and restoration for years.

Low tech application, but it can be (should be) applied to a moistu concrete surface. Additives can be added for improved properties. If you use multiple coats, make sure you follow the suggested timing between coats to get maximum performance.

timbo · 01-10-2007, 11:26 PM

thx, as the walls of the tank are very porous as a result of being sprayed concrete (shotcrete) should i trowel a thin layer of render on first, or can you mix thoroseal with the render.
thank you for your help...

concretemasonry · 01-11-2007, 08:20 AM

You can trowel on a coating if you wish. This will be determined by the texture of the shot crete.

Do not mix Thoroseal with the rendering and try to create a new system that may not work.

Mix and apply Thoroseal as directed. When mixed, Thoroseal will be similar to pancake batter. Apply to a moistened surface.

timbo · 01-11-2007, 08:32 AM

thank you the surface has finger tip size holes in it at present.

tkle · 01-12-2007, 05:06 PM

Quote:

Originally Posted by timbo

thank you the surface has finger tip size holes in it at present.

Superblockade(Merlex),I believe already has the latex additive.I'd parge first and get the surface as free of voids as possible,leaving it a little rough so the sealer will bond better.Make sure and let it slack after mixing as per instructions so that the waterproofing agents have time to hydrate.Dampen the surface and apply thin coats.

concretemasonry · 01-12-2007, 05:20 PM

It sounds like Thoroseal and Superblockade are the same products.

Be sure about the timing of secondary coats.

For Thoroseal, a slightly wet or damp concrete surface makes the application easier and produces a better product in the end.

Thoroseal copies/knockoffs are also frequently used for similar applications (water tanks, cisterns, etc.) across India in addition to general concrete surfacing and coatings. Not exactly the same, but still effective.

tkle · 01-12-2007, 08:39 PM

I'd say SB is a knockoff of Thoroseal.Most guys around here prefer the SB though I don't see much difference.The question is what's available in Australia?

concretemasonry · 01-12-2007, 09:09 PM

tkle -

I do not know about what is available in Australia. I am sure someone has copied the formula.

They could be the same or possibly the silica sand in finer in one than the other. I don't think there is a difference in the chemicals. I have thought there was a difference between the white and gray Thoroseal, but that is probably due to the difference in the cement used.

tkle · 01-12-2007, 10:28 PM

Quote:

Originally Posted by concretemasonry

tkle -

I do not know about what is available in Australia. I am sure someone has copied the formula.

They could be the same or possibly the silica sand in finer in one than the other. I don't think there is a difference in the chemicals. I have thought there was a difference between the white and gray Thoroseal, but that is probably due to the difference in the cement used.

The only difference is the white costs more.If you don't care about color get the grey.

tkle · 01-12-2007, 11:21 PM

Thoroseal known internationally as masterseal bought out by Basf last July.

http://www.basf-cc.com.au/sealant/seal13.htm

concretemasonry · 01-13-2007, 09:23 AM

The Masterseal referenced is a 2 part (liquid & powder) FLEXIBLE MEMBRANE. It does not sound like Thoroseal and the allication and physical properties.

The link to BASF is certainly possible since most concrete-related products seem to be the takeover targets of huge international congomerates because of the huge projected increase in the replacement of temporary products like wood.

The U.S. investors have lost ownership of virtually all cement production and since then, the use is up and new efficient, ecologically production facilities are increasing.