liquid membranes & adhesion

[2010]

if using a liquid membrane this obviously creates a barrier between the adhesive and the substrate so how good is the adhesion of this?
what weight per square will they typically carry?

 

[Ajax123]

Depends on the adhesive. Normally I would expect either a smoothing compound to be placed over the dpm prior to coverings or use a sand broadcast into the second coat of the dpm to provide a rough textured finish for the adhesive to key to.

Liquid membranes are not designed to carry weight as such and are generally only 600microns thick anyway. Any weight on top will be transferred directly to the subfloor. The weight carrying capacity of the dpm itself is negligible.

 

[2010]

thanks for your reply

I was referring to a tanking membrane on the walls not floor and concerned about it peeling away similar to the way pva might

 

[Ajax123]

thanks for your reply

I was referring to a tanking membrane on the walls not floor and concerned about it peeling away similar to the way pva might

Ah sorry I misunderstood. In that case being a floors kind of guy I am unable to answer your questions. However I am sure someone will be along to do so shortly.

 

[DHTiling]

I had this conversation with Mapei... after it was mentioned on here that using a liquid tanking would reduce the substrate capacity by around 10kg per sqr mtr.. or summit like that..

I discussed this and after a call to tech , it was said that NO it does not reduce it and if it did it was negligible..

Also for reference to others who use tanking membranes, they also do not reduce the capacity..

 

[Gazzer]

Manufacturers of such systems have claimed in the past that it will be the same weight limits as the original substrate....well thats what I was told when I asked.

 

[Diamond Pool Finishers]

well with the greatest respect what have they based there theory -on ,it's all very-well some random on a telephone saying so then you guys just repeating it , surly they should explain in technical detail

 

[DHTiling]

Some random... :lol:..

It was head of tech dave... maybe he is random..

 

[Gazzer]

well with the greatest respect what have they based there theory -on ,it's all very-well some random on a telephone saying so then you guys just repeating it , surly they should explain in technical detail

he may well have done but I may not have taken it all in.....I prefer dural/ditra membranes instead.

 

[2010]

thanks for the replys, its ordered now so i will have to go with it but it sounds like it should be ok

 

[Polishtradesman]

Remamber to use class c2 adhesive for surface with tanking membrane ( or somethng which is suitable for surface which does not absorb water)

 

[JFRWhipple]

I've seen liquid membranes peel away from the backer boards when those backer boards where not first cleaned of dust and bond breakers. I have also noticed that liquid membranes peel away easier if only rolled and not brushed on the first coat. As a rule we clean the backer board first and tape all our backer boards with thinset and mesh tape. The next day we give the walls a clean and use a brush to burn the material into the pores of the backer board. On the first coat we treat the first pass as a primer and hit it again with a coat. Then a second coat the next day.

I have removed tiles with Aqua Defence from Mapei with no bond failure from the liquid and have inspected other setters work where I could peel away sheets of it. Like any tile failure I'm sure the number one reason for liquid membrane failure would be bond breakers.

JW