Flat roof/patio waterproofing systems

theoptimist

Does anyone have any experience of products/systems such as Thoroseal and Botament?
I'm looking at both systems for a patio with living space underneath.

At the moment we have the concrete slab with concrete screed
The Botament rep recommended this concrete be sealed with their paint-on product, then insulation, screed with a fall, their sealant/adhesive with a membrane laid/stuck down to it (overlapping with adhesive used to seal joins), then tiling using the same adhesive and their grout.

The thoroseal appears to be just a paint on product, (cement based tanking slurry) however the guy in The Damp Store says they've been using it for 40 years with no problems. Maybe simpler is better?!

The botament seems to have more layers of protection however... their paint-on product sounds very like the thoroseal but is only the final layer of protection in case everything else fails.

How do I decide what to use?!

Safehands

theoptimist wrote: »

Does anyone have any experience of products/systems such as Thoroseal and Botament?
I'm looking at both systems for a patio with living space underneath.

At the moment we have the concrete slab with concrete screed
The Botament rep recommended this concrete be sealed with their paint-on product, then insulation, screed with a fall, their sealant/adhesive with a membrane laid/stuck down to it (overlapping with adhesive used to seal joins), then tiling using the same adhesive and their grout.

The thoroseal appears to be just a paint on product, (cement based tanking slurry) however the guy in The Damp Store says they've been using it for 40 years with no problems. Maybe simpler is better?!

The botament seems to have more layers of protection however... their paint-on product sounds very like the thoroseal but is only the final layer of protection in case everything else fails. How do I decide what to use?!

I do not know the botament system. Thoroseal is well tried and tested and is effective. If you anticipate any movement then the Thoroseal may not be sufficient. I have seen balconies waterproofed with Liquid Vapour Membrane by Parex. It is easy to apply, accommodates movement and I don't think it is too expensive.
Is the Botoment Rep suggesting you place another screed on top of your existing screed?

theoptimist

Hi Safehands, yes I am getting that impression of Thoroseal right enough.
We will have to have another screed as the current one is just a flat structural screed on the slab that only extends to the inner leaf of the walls. The plan was always to insulate above this and then have a screed with a fall. I am just a bit puzzled by the Botament rep suggesting the bottom screed be sealed, in fairness to him his technical guys have said this layer should be vapor proof to prevent water vapor coming up from the rooms underneath, (?) and this is not something they do so he isn't just trying to flog me loads of stuff!!

Since my first post I have done a good bit more research and I do like what I'm hearing about the Thoroseal. The guy in the damp store sounds very down to earth too, saying there are a lot of layers of protection there with the tiles, grout, adhesive and tanking slurry. You can spend as much as you like adding more layers but there is really no need for it as he sees it.
Its a fair point, I would just instinctively be happier with something that has some crack bridging ability in the case of the concrete developing any small cracks as it dries (which I am told would be quite common).
The other system I was talking to someone about today is a painted flexible sealent with a mesh laid on top and then another layer of the painted sealent on top. I like the idea of this, no membrane with joins that could develop weak points and a flexibility to accomodate any slight movement. May be very expensive though, they haven't given me a price yet.

Safehands

theoptimist wrote: »

Hi Safehands, yes I am getting that impression of Thoroseal right enough.
We will have to have another screed as the current one is just a flat structural screed on the slab that only extends to the inner leaf of the walls. The plan was always to insulate above this and then have a screed with a fall. I am just a bit puzzled by the Botament rep suggesting the bottom screed be sealed, in fairness to him his technical guys have said this layer should be vapor proof to prevent water vapor coming up from the rooms underneath, (?) and this is not something they do so he isn't just trying to flog me loads of stuff!!

Since my first post I have done a good bit more research and I do like what I'm hearing about the Thoroseal. The guy in the damp store sounds very down to earth too, saying there are a lot of layers of protection there with the tiles, grout, adhesive and tanking slurry. You can spend as much as you like adding more layers but there is really no need for it as he sees it.
Its a fair point, I would just instinctively be happier with something that has some crack bridging ability in the case of the concrete developing any small cracks as it dries (which I am told would be quite common).
The other system I was talking to someone about today is a painted flexible sealent with a mesh laid on top and then another layer of the painted sealent on top. I like the idea of this, no membrane with joins that could develop weak points and a flexibility to accomodate any slight movement. May be very expensive though, they haven't given me a price yet.

Yes, I agree with that. The Eproseal I mentioned is such a system. You are obviously doing good research and asking the right questions.

theoptimist

Thanks Safehands!! If I mess up it wont be for the lack of effort!! You mentioned Liquid Vapour Membrane by Parex and I forgot to say thanks for that. Is Eproseal another name for that product? I'll have a look at it today

Safehands

theoptimist wrote: »

Thanks Safehands!! If I mess up it wont be for the lack of effort!! You mentioned Liquid Vapour Membrane by Parex and I forgot to say thanks for that. Is Eproseal another name for that product? I'll have a look at it today

Sorry, the Liquid Vapour Membrane is the one with flexibility, I sometimes get confused with all these names. Eproseal is the same as Thoroseal, which is not flexible. Incidentally, if you are interested, there are materials out there which are Cement based slurries like Thoroseal or Eproseal, but they are Flexible as well. They are quite expensive though. Fosroc do one, so do Parex, I'm not sure about Thoro or Sika. I expect they do.

theoptimist

Ok, that sounds good, flexible slurries. The cement based slurries sound pretty effective so add a bit of flexibility and I'd say they're very good. I'll see can I find someone who does them tomorrow.

A company I spoke to today does a hot applied modified bitumen and a cold aquablocker. He says they both perform very well but the hot applied is good because it retains its flexibility indefinitely and because it bonds so well to the concrete that if it ever was breached in a point the water can not travel between it and the concrete. At (very approximately) €35-40/m2 it seems to be about 50% more expensive than the thoroseal. (this is just from the ball park figures I have been asking for, not proper estimates)

I'm looking forward to seeing the price on the three layer, sealant-mesh-sealant product that Bidcon do. Still like the sound of that.

theoptimist

Do you think it would be overkill to add one of the waterproofing products to the concrete for the screed? Just saw one on the parex website. Any idea what products like these add to the per m3 price of the concrete? Lazy question, I'll check it out tomorrow!

theoptimist

The three layer liquid-mesh-liquid is about €120/m2, no surprise there, the product that sounds the best is by far the expensive!!
They also have a vcl, 120ml insulation then pvc membrane that would go on top of the falling screed at a fairly reasonable cost though, anyone heard of this?