Installation of hardiebacker 250/500

[Ian]

There have been a few threads recently asking questions about the correct procedure for overboarding wooden substrates with hardiebacker cement board. I did one earlier in the week and took a few photos, so hopefully this will help answer a few questions.

First things first, hardiebacker provides no extra structural strength to the substrate, any deflection MUST be rectified prior to its installation.

22mm chipboard substrate, hoovered and primed with SBR.

Boards cut to size using a carbide scoring tool, usually 3/4 deep scores are enough, then snap the board.

Boards are then stuck to the substrate using a SPF adhesive, some people have mentioned that a non flexible adhesive will suffice, I disagree, I think it is good practice to use SPF throughout an install on a wooden substrate.

A 4/6mm trowel is used to spread the adhesive.

Boards are laid in a brick bond fashion, and on larger floors can be laid in herring bone to shorten the joints. 2/3mm spacers are used to create an expansion gap.

Boards are screwed to the substrate while the adhesive is still wet, this install was hardiebacker 250 (6mm) so 25mm screws were used. Screws have been placed at 200mm centres, approximately 30 screws per 1200x800 board.

After sticking and screwing the boards, remove the spacers and tape the joints with an alkaline resistant tape.

You are now ready to tile!

Here is a link to the James Hardie web site for any additional information and safety advice http://www.jameshardie.co.uk/developer/products-backerboard-hardiebacker250.shtml

I hope this is of use to someone, if I have missed anything, let me know and I'll edit it in.

Cheers Bri.


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[Tony73]

nice . My long term client (construction company) have decided to use marmox boards, just started on new project and fixing 4mm marmox on walls, on top of plasterboard. (use tile adhesive) wuold you also screw it?

 

[Ian]

nice . My long term client (construction company) have decided to use marmox boards, just started on new project and fixing 4mm marmox on walls, on top of plasterboard. (use tile adhesive) wuold you also screw it?

I would yeah, if it's on stud walls, find the frame and screw through into it, if block walls, plug and screw.

 

[Tony73]

thanks Bri, yeh that is i wished to do, but walls were skimmed, so not easy to find timber behind :lol:. But for now i did go with 4mm trowell horizontally on wall and vertically on board (with tile adhesive)

 

[swanman]

Great post bri

 

[appletiler]

thanks bri like the spacers bit and the screw down while wet bit .

 

[mac mclaren]

Great advice and pictures well handy info thanks

 

[suave]

the joints should be skimmed over the tape and feathered

 

[Ian]

the joints should be skimmed over the tape and feathered

I always do this as I'm tiling, that way it's all tied into the adhesive bed.

 

[suave]

fair point bri al do that next time only laid it a couple of times,good post

 

[Stef]

Bri, i was having trouble with the screws snapping when fixing the boards down, 25mm stainless screws , so i started using 25mm clout/roofing nails to fix them down, is this ok?

Im not sure if i got advised to do this or read it somewhere.

 

[Ian]

Snapping screws? How strange. Screws are definately better than nails as they pull the boards into the adhesive, I'd be a bit concerned about voids if nails were used.

 

[suave]

a tried the the clout nail method thinkk the addy went off nails kept bending lol

 

[CJ]

Don't use the hardibacker ceramic coated screws...........Orrible things

Stainless screws, and even then you may need to pilot hole, & the countersink the holes.

Hardibacker........good stuff.........orrible to use. Blunts ya gear.

 

[Ian]

Have you got the carbide scoring knife CJ?


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[Perfect Tiling]

Good post Bri. I always walk around on the board straight after laying just to help bed into the adhesive. Have done larger floors and used a colated type screwgun which saves a lot of time...also saves your fingers from the pozi bit going into the bone...ow. It still hurts!!!! I always trowel over the taped joints same as suave then feather out with a damp sponge...looks good when all done and much better than ply.

 

[Stef]

Snapping screws? How strange. Screws are definately better than nails as they pull the boards into the adhesive, I'd be a bit concerned about voids if nails were used.

The screws we bought were from Screwfix, stainless steel, I was putting them in with an impact driver & the heads were snapping off of a few of the screws. Not sure if the impact driver has too much torque as im driving the screws home.

I walk over the sheets when stuck down so they are getting a good bond then nail them straight away, you can see the nail pulling the board into the adhesive.

We have never had a failure using this method yet but thats not to say it is the right method.

I had to rip up a cutting (200mm X 800mm) of hardie from a chipboard floor & i couldnt believe the grip it achieves,

It took me a good 10/15 mins to get it removed.

 

[Diamond Pool Finishers]

The screws we bought were from Screwfix, stainless steel, I was putting them in with an impact driver & the heads were snapping off of a few of the screws. Not sure if the impact driver has too much torque as im driving the screws home.

I walk over the sheets when stuck down so they are getting a good bond then nail them straight away, you can see the nail pulling the board into the adhesive.

We have never had a failure using this method yet but thats not to say it is the right method.

I had to rip up a cutting (200mm X 800mm) of hardie from a chipboard floor & i couldnt believe the grip it achieves,

It took me a good 10/15 mins to get it removed.

wow an impact -screwdriver ! i thought they were for removing rusted screws ,surely a normal battery driver would do Robson,lol

 

[swanman]

I use my grinder to cut the hardi board

Works well

 

[Stef]

wow an impact -screwdriver ! i thought they were for removing rusted screws ,surely a normal battery driver would do Robson,lol

Once you use an impact driver you will never go back to using a normal battery gun again, they are far too heavy.

I only use my battery gun for cores & drilling some holes.

 

[Stef]

I use my grinder to cut the hardi board

Works well

Hope you use a good dust mask & cut it outdoors as the dust is toxic. :yikes:

 

[Martino]

When you fix the board with adhesive can you tile onto it straight away?,,,,i have also heard people just using pva to stick it down and screw it too. whats wrong with this way?

 

[prceramics]

2nd that impact driver with a gold bit use rapid set tile adhesive then screw, then tile straight away

 

[Andy Tiler]

When you fix the board with adhesive can you tile onto it straight away?,,,,i have also heard people just using pva to stick it down and screw it too. whats wrong with this way?

Once the board is fixed when your ready to tile just wipe it down with a damp sponge! And tile away

 

[gamma38]

Top post Bri:hurray: