Anhydrite screed & Laitance removal - TilersForums.com

[Ajax123]

Yes, but not me personally. I know it needs to be primed & ideally use a gypsum-based adhesive. The other half of the floor will be engineered wood.

It depends on timescales. There is a new system about to be launched which will allow tiling to commenced on Gypsol Anhydrite screeds after just 7 days and with a moisture content up to 95%rh. Should be available after 1st July.

 

[Ajax123]

It is the Tramex CEMexpert II

Not suitable for accurate moisture measurements on Anhydrite.

 

[Holster]

So what would you recommend Ajax? Also been doing hygrometer box RH tests

 

[Ajax123]

So what would you recommend Ajax? Also been doing hygrometer box RH tests

Hygrometer is ok. Carbide bomb Is most accurate.

What sort of temperatures have you run the underfloor heating.

Independent tests tell us that if force drying with underfloor heating the presence of laitance does not interfere with drying times.

 

[One Day]

I wish MY customers took an interest in moisture readings and sanding screed! It's always left to me to raise the issue, convince the client and take the readings and usually sand the screed!

 

[Holster]

It's been at 55 degrees. I'll be honest, it's the engineered wood I'm more concerned about going down too early. If that ends up lifting it's mega bucks.

 

[Holster]

Ajax, I did read that too, but it does depend on the thickness of the laitance... ours was seriously difficult to remove (and it's all I have to hold on to right now to get the moisture levels down). The difference in the two textures (unsanded vs sanded) is staggering.

5.2 The effect of removing laitance. In the areas tested no effect on drying times was apparent whether the laitance was removed or not. It is acknowledged, however, that this tested a screed produced with a single sand source and different screeds may produce differing thickness and densities of laitance.

 

[Ajax123]

I will have a word with one of my contacts. He has a special disk that cuts the laitance off quite quickly. I can't remember what it's called though. I'll be back...

 

[Spacey]

Wolf samba/wirrble or wolf mamba with ninja disc and PCD grinding bits works a treat no matter how long the laintence has been left.