Waterproofing Pool

[ajk1]

I am designing a rowing pool. The American architect who has done these pools in the past says we should use an integral crystalling wayerproofer in the concrete and no external waterproofing membrane. But the manufacturer's liteature for the crystalline waterproofing says it can waterproof only cracks only up to 0.4 mm wide. I think we should design the pool in accordance with the ACI guide for water retaining structures, but can we be comfortable with not using a waterproofing membrane? I have used integral crytalline waterproofing in baseemnt walls, but I am not sure that I have ever done a pool without a waterproofing membrane. Anyone on this forum done a pool with integral crystalline waterproofing and no membrane, and if so, how did it turn out? (The architect also recommedns a surface siloxane paint, but I can't see how that is going to do much good against a head of water).

 

[hokie66]

Concrete pools don't generally have a membrane, unless in an elevated area of a building. If you design it as a water retaining structure, the reinforcement limits the crack widths. Also, water retaining structures with minor cracks will seal themselves. It is called "autogenous healing". The crystal type admixtures do assist in that healing process, but should not be considered as waterproofing.

 

[JedClampett]

I'm not a believer in the crystalline waterproofing compounds. For one, they only commit to helping with tiny cracks. For another, if there is Fly Ash in the concrete, they have to loose calcium to activate with. For another, they tend to oversell their benefits, which makes me suspicious.

 

[BAretired]

I have used Xypex, Vandex and Krystol without problems, but also have used nothing but water stops at joints between slab and wall. Usually, a hydrostatic test is performed before turning the project over to the owner. In my experience, with or without waterproofing, there was some loss of water at first but the concrete eventually sealed itself as hokie suggested.

Hard to say if the crystalline waterproofing did any real good, but it didn't hurt.

BA

 

[Ron]

Integral "waterproofing" compounds don't work. Good quality concrete, low w/c ratio, dense placement are better than supplements.

 

[ajk1]

Ron - about 3 years ago we used integral waterproofong on a large project in Bermuda where the basement walls were constructed during low tides. I am told the walls in the completed building do not leak, even at high tides. So I think the integral waterproofing did some good. I don't think that the manufacturers' claims can be totally bogus or they would be being sued by now. Where I am uncomfortable with it is when wider cracks form or where the cracks form some signifcant time after the concrete is placed. I cannot see how it can take the place of a membrane, and I believe that we have done pools with a membrane. probably more of a question of whether some leakage is acceptable in preference to spending more money on a membrane. In any event, low w/cm reduces permeability but I cannot see how it helps leakage at cracks. Your comment is more relevant to the prevention of corrosive chemicals permeating the concrete (as in a praking structure) but I don't think that is a problem in a pool.

JedClampett; the manufacturers say that it is good for cracks <0.40 mm which is not so tiny.

Hokie66: I am well aware of autogenous healing but I would not rely on it happening. I like something more assured of happening .. if it leaks I am not going to look good if I say I relied on autogenous healing.

 

[hokie66]

If you provided a membrane in a swimming pool, what type would you use? Just wondering, because I don't think I have ever seen what I call a membrane used. There are fibreglass pools, vinyl liner pools, aluminum pools, painted pools, tiled pools, but I don't call those membranes.

Is this pool in ground or suspended?

 

[Ron]

ajk1...I agree they have some affect, but when there is a potential for cyclic wetting and drying, or continuous submersion, I have not seen them perform to expectations.

I have not seen them used much in critical situations (by choice), but have seen their effect eroded with time in applications. They certainly don't hurt; however, I'm not ready to believe the mfr claims either.

They are commonly used in masonry production and architectural pre-casting; which is specifically where I've seen the erosion with time.

 

[ajk1]

Ron;

Thank you for sharing your experience. Much appreciated. My application is in reinforced concrete pool.

Follow up questions, for those with experience with pools:

a) do you put vertical construction joints at any particular centres along the pool wall?

b) what is the minimum horizontal reinforcement you use in the walls to ciontrol cracking/leakage? I assume it would be something much more than 0.002Ag. I was thinking of perhaps 0.0060 Ag which for a 300 thick wall works out to 900 mm2 per m perface or 15M @ 220 centres per face.

 

[ajk1]

I just found out that the crystalline waterproofing manufacturer offers no performance guarantee, so perhaps you are right to say it is useless.