adhesive for Hardiebacker board

[stevethejoiner]

Hi guys

This is probably a question that has been asked before so my apologies if it has but I have a large quantity of limestone to lay onto Hardiebacker and want to know if I should use a cheaper adhesive..

My new house is a suspended timber floor construction, mostly chipboard on joists but some 8x4 ply on joists.
I have 5 rooms to do so over 80 square meters to cover.
I am covering all the timber with hardiebacker board first.

Hardiebacker say the board should be laid onto a bed of flexible adhesive, and my limestone will also require flexible adhesive and white.

With coverage at say 3mm thick I am going to need quite a lot of the stuff to cover 160 square mts . My estimate is 360kg thats 18 x 20kg bags

The thing is have been looking on line and I find Granfix FastSet flexible 20kg at £10 or Mapei Keraquick is about £40 for the same qty.

If I were doing one room I would go with Mapie but £180 is a lot different to £740

Dare I use the cheaper adhesive?

Thanks Steve.

 

[tpt]

granfix is a premium adhesive, no worries there. you'll have full technical backing. We specify it for very large jobs in brand name stores all the time. You can use grey behind the hardiebacker and white between it and the limestone to keep the cost down. Mapei certainly isnt considered a premium adhesive compared to granfix - you'd be looking at bal or ardex to take a 'step up' and even that is subject to opinion.

One thing i would be cautious of is using any adhesive directly onto waxed chipboard as nothing sticks well to it. If you wish i can have a chat with granfix and see what they say, they will provide a full spec for you if you wish, which then carries a 25 year warranty for you, although they do tend to overspecify some times.

hardie is great stuff, but we supply no more ply all the time which is a cement backer board and is a lot cheaper than hardie. You fix this down with grab adhesive (like no more nails) and screws. Never had a failure in years.

One last thing, i think you will need more than your calcs show, unless your only talking about the amount to fix the hardie down.

I'd be happy to specify/quote for the lot if you want to PM me?

 

[AdamCH]

You can get Weber Rapid SPF for £12 a bag. You can get Ardex X9 for similar from http://www.pureadhesion.co.uk/tile-adhesive.html

Hardie 6mm is £8 per board from http://www.insulationexpress.co.uk I think I've had it cheaper from them in the past so might be worth shopping around.

 

[stevethejoiner]

Thanks Guys

I already have backer board. Its just advice on adhesive I wanted and thanks to you, I have got.

Cheers Steve.