hardibacker again

[brailesbuilder]

Hi, I.ve built a new shower in an old property and needless to say one wall was about three inches out of upright. This was not a problem as we were using hardibacker and could rectify by dabbing it with drylining adhesive. Trouble is, it didn't stick. Should I have used pva? It stuck very well to the existing (out of level) wall which I did pva. Should I pva prior to tiling? I suppose I've just answered my own question. I was just a bit surprised at it non stick quality.

[jay]

hi don't recommend using pva best to use acrylic primer might help to prime back of hardie to eliminate dust issues you are asking a lot to build out 3 inches might be best to stud out or if wall is brick render plumb hope this helps

[diamondtiling]

I think you would be wise to mechanically fix as well, as Jay has stated you are asking a lot with gaps like that. Have a look at their websites technical info.


James Hardie: HardieBacker 500 backerboard | Residential Siding from James Hardie

[faithhealer]

am I right in thinking you can't / shouldn't dot and dab hardiebacker?

[diamondtiling]

I dont use a lot of hardi backer but if its the same as aqua panels then dot and dab is a no no.

[Dave]

am I right in thinking you can't / shouldn't dot and dab hardiebacker?

I dont use a lot of hardi backer but if its the same as aqua panels then dot and dab is a no no.

Spot on lads....No it should not be dot and dabbed....

[tfs]

Hi, I.ve built a new shower in an old property and needless to say one wall was about three inches out of upright. This was not a problem as we were using hardibacker and could rectify by dabbing it with drylining adhesive. Trouble is, it didn't stick. Should I have used pva? It stuck very well to the existing (out of level) wall which I did pva. Should I pva prior to tiling? I suppose I've just answered my own question. I was just a bit surprised at it non stick quality.

Its becuase it is moisture resistand mate. A normall adhesive will not bond to the board. When you are installing on a floor Knauf advise you to install with an C2/S1 classified adhesive.

Based on that advise you will need a Polymer modified adhesive rather than a basic bonding compound. It would also be worth noting that most adhesives that would be suitable for aquapanel have limitations to the depth of bed you should make e.g. 10mm etc

[brailesbuilder]

Sound advice everyone, raising issues I'd not thought of.
Many thanks,
It is onto 15th century lath and plaster and may have exaggerated the three inches a bit, its 52mm at the worst point. I have dabbed it and got a good fixing into oak studs which I'll tighten tomorrow. I can't really stud it out as its tight at the bottom and stripping back the plaster would be a swine as obviosly some of the laths are long and I'd have half a wall on the floor, plus its nice to preserve where poss.

[tfs]

I agree with the 'nice to preserve' comment mate.

[whitebeam]

I would'nt be using dry wall adhesive with cement board