Discussion in 'Tiling Forum' started by Alexb, Jun 13, 2016.
Discuss Hardiebacker in the Tiling Forum area at TilersForums.co.uk.
Hi, does hardierbacker in bathroomneed to be primed before tiling?
No it doesn't. Please say it's not in a wet area?!
It is in wet area. Is that a problem?
It's not waterproof. Absolutely pointless putting hb in a wet area. If you want it waterproof, you'll have to tank it now. Hb is mis-sold as suitable for wet areas. What it does is allow water to pass through to the background.
I thought it was waterproof, heard a lot about it. If that is the case, then it is better just to usetanked plasterboard
Water safe not waterproof meaning water don't make it deteriorate
Hardie in a shower I've just completed.
It needs tanked to be waterproof.
Tanked plasterboard is waterproof, and if hardiebacker also needs to be tanked, what is the difference between them, apart from the price?
Which when tanked comes right down.
No way a paint on system can take the full quota.
You would have to use a membrane such as Kerdi.
surprisingly some tanking kits say they don't alter the substrate's hanging weight. @Paul C. posted something about it a while back. i think ardex's one was one if memory serves.
I only put Hardie on walls (which is rarely) if the tiles are heavy.
Thanks everybody for the comments, will stick with tanked plasterboard.
I know - I remember the post but I am pretty confident I can "peel" ardex wp off hardibacker.
I'm a big fan of ardex wp but I can't believe the claim - sorry!
Does not need to be primed but I would advise you to wipe it down with a damp cloth just to wipe off dust. It will dry in a matter of seconds.
Sean Kelly - do you mean does not need to be primed before tanking?
No. I was just answering yr original question. It does not need to be primed.
When you say a wet area do you mean shower? Tanking is belt and braces. I personally would not tank Hardiebacker as long as you seal with scrim tape and adhesive. Also using silicone before and after tiling.
Alex you haven't told us what you are tiling. You might be better off using Marmox type boards.
Marmox, Wedi etc type boards for me on walls over the cement type boards (Hardie, No more ply, etc). They are so much lighter to transport and carry to the bathroom; cutting is much easier (sharp knife (old wood saw sometimes)); Waterproof and joints can be glued sealed (eg Wedi 610 board sealant/glue) to waterproof them so no need to prime or tank; they are also insulating.
Give this man a banana! He gets it!
Hardi rep told me if primed it is totally water proof and suitable for wet rooms (assuming joints are sealed).
Not done it myself but that is what Hardi say.
By primed, he must mean tanked
Nmp primed, with their primer, is also waterproof or so I've been told
It wasn't the Hardi rep it was the NMP rep -I get them mixed up.
Insisted with their primer NMP is perfect for wetroom installations.
i wouldn't trust it though and doesn't say it anywhere,that i can find, in their bumf.
"perfect" as in "completely unsuitable"?
I've not used nmp but it's basically the same as Hardie, a cement board.
There is no way that is deemed waterproof using their primer.
The only boards that are waterproof are the poly extruded ones ie marmox, wedi etc.
from "no more ply" document:
"To make NO MORE PLY boards completely waterproof, coat the completed NO MORE PLY surface with two coats of SBR primer (one part SBR to three parts water)."
I've done this in the past and not worried about it but I did like to use a secondary tanking tape in critical corners to back up the glued joint.
However I would always go for Wedi in preference to it on walls for the reason given in my earlier post.
Sorry my post got split (finger on keys trouble)!!
I'd never use it for that kind on install, it just feels wrong.
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