Sticking down cement based boards

[Gazzer]

Gotta say its all a pain in the wotsit, prime floor and then each board both sides ???? I wont be doing it again. :mad2:

 

[Ajax123]

These ones not dusty at all. Dull one side and shiny the other. Dull side goes against the substrate and the shiny side is the finished floor. Not supershiny but sort of Egg Shell finish....deffo not no more ply. Also has no makers stamp on it ....

 

[DHTiling]

Deffo a faff neale...



Can't recall a board like that Alan... is this for you or just a job you were on..?

 

[Ajax123]

It's a job I been to see today. Got some issues with the floor having popped using dot and dab. I know why it popped but now want to make sure it don't happen again. Needless to say it is complicated by being anhydrite. Can't use gypsum adhesive cos it will react with the board as well.....Doh!

 

[DHTiling]

It's a job I been to see today. Got some issues with the floor having popped using dot and dab. I know why it popped but now want to make sure it don't happen again. Needless to say it is complicated by being anhydrite. Can't use gypsum adhesive cos it will react with the board as well.....Doh!

Why... The portland has cured.. so gypsum is fine.. it is the other way around when portland hits gypsum...that is why plasterers can skim cement render with gypsum finish..

 

[grumpygrouter]

I tried this once with hardie 250....the boards ain't flat and the addy wasn't strong enough to pull it down......i had to drill and plug the floor to pull the boards down!!

 

[Ajax123]

Why... The portland has cured.. so gypsum is fine.. it is the other way around when portland hits gypsum...that is why plasterers can skim cement render with gypsum finish..

The issue is that I have no idea how these boards are made and if all the cement is fully hyrdated. If there is any unreacted cement as soon as the water in the addy and the residual moisture in the screed (allbeit only 0.5%) the ettringite reaction can begin. Think it not a risk I would want to take in this instance. I guess thinking about it though the H40 Ideal might be a good one for this....hmmmm will ring kerakoll tommorrow I think.

 

[DHTiling]

Worth a thought.....Still would like to know what board it is..

 

[Ajax123]

Worth a thought.....Still would like to know what board it is..

As would I Dave...as would I. If I can find out I will let you know. just been scanning the net and can't find anything very similar.

 

[DHTiling]

Sounds like the knauf one...