Tanking on hardiebacker

[jgw1]

Hello one and all,

I am about to refit my bathroom, the old plasterboard was dot and dabbed onto breezeblock however this has failed to hold the weight and is bulging at the bottom.

As well as replacing the suite I have decided to replace the wall as I want to do a proper job.

I have bought Hardibacker for the walls that need to be replaced and was wondering about tanking it. I have heard different opinions on the need to tank when using backer boards - what do people think? Tank or no tank?

If I have to tank can the BAL system be painted directly onto the Hardiebacker? I know I have to prime the back of the boards and the edges with BAL SBR Bond (I checked with BAL) but it explicitly says no to apply this to the facing to be tiled. If the tanking kit is similar to BAL SBR bond then I am not sure that I want to be using it on the Hardiebacker if it will compromise the surface for the tiles to stick to.

jgw

 

[Benny]

Mate
there is no need to seal the backer board on the back and edges as it is water resistant, you only need to do that with ply. To make the backer board waterproof use the BAL WP1 and prime it first with APD (comes with the kit) let it dry then tile, for best results use flex powder as you will get delayed drying with tub addy onto tanking

 

[jgw1]

Thanks for the help.

In the BAL Tanking kit instructions it says,

Surface considerations:

FIBRE CEMENT SHEET BACKGROUNDS: Ensure that
sheets are dry, securely fixed and rigid and fixings do not
protrude. Seal exposed edges of sheets with BAL-BOND
SBR but do not seal or prime surfaces to be tiled. Check
suitability of sheets for the intended application with the
manufacturer.

I took it that because the board does not seal the enclosure but only resistant to water (it won't rot) you still need to seal the back and sides to prevent any water getting through to the studs behind? Any thoughts?

 

[DHTiling]

For a totally waterproof installation then yes tank it out.......and use the tape provided with the kit for the joints......The tanking kit will prevent any moisture from transferring through the boards to the timber studs.......as you say the are water resistant boards that will not be affected structurally by water but they will wet up when exposed to prolonged water contact........

 

[jgw1]

Cheers,

Would most bathroom fitters tank a bathroom then?

 

[wetdec]

Hi

I would say that tanking or waterproofing showers should be done as by spendin £100.00 on having the job sealed properly you can be saving a fortune on damage.

If your insurance excess is more than £100.00 then you have saved already.

I would also add that its the tanking membranes which are the way forward and provide a true tanking solution as oposed to paint on gum membranes


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