Which backer board

[rj1884]

Good evening all. I'm starting 2 bathrooms on of which has 22mm chipboard fixed to the joists and the other has 18mm ply, fixed to joists. Both floors are solid. I've used hardie in the past and found it to be ok to use. I've read a lot about marmox and dukkaboards to overlay which is apparently slightly easier to use. From all your vast experience what do you all prefer to overboard with.

 

[cam_low]

Jackoboard. Hardies old news these days

 

[White Room]

For overboarding 6mm hardie glued and screwed.

 

[martin1c]

Love Marmox. Light and easy to cut

 

[johnryan]

Jackoboard. Hardies old news these days

never seen that before. what's the price like? is it easy to use.

 

[lizzardtong]

5.99 +vat at ctd 1200 by 600 mm for 6 or 10mm

 

[johnryan]

5.99 +vat at ctd 1200 by 600 mm for 6 or 10mm

is that the new boards they have on the offers sheet. meant to ask them about those. very good price for them if they're any good. do they do the thicker sizes?

 

[lizzardtong]

Thats the ones. Not sure if they do other sizes. Give them a ring.

 

[rj1884]

Cheers for your replies. Martin1c, when using marmox on these floors would you use 6mm boards. Cam_low, what's the minimum thickness of the jackoboard on these floors. Good price as well

 

[martin1c]

I think 6mm should be fine. Just make sure that you stick with the basics, flexible adhesive and screwed down every 6-8 inches using the plastic or metal washers

 

[judge]

Whats the difference between the jackoboards and the hardi ?

 

[lizzardtong]

Ease of use and insylation properties

 

[charlie1]

If using hardie then use standard cement, not flexi. Hardi advise this! I know I know, everything is telling you to use flexible, I thought so too... We live and learn 🙂

 

[White Room]

I still use flexi, it has'nt let me down...

 

[charlie1]

I still use flexi, it has'nt let me down...

if you do ever get a failed floor then don't give them an opportunity to pass blame, follow manufacturers instructions.

 

[2020Tiling]

Hardy with spf all day long.. I never knew the advised against it. surly it can only help?

 

[charlie1]

They categorically advise non flexi adhesive. If I remember right, the adhesive is in no way there to stick the boards down, it's simply filling the voids between the board and timber. So as a void filling entity, I can see why non flexi would perform better and increase the rigidity of the floor.

 

[White Room]

if you do ever get a failed floor then don't give them an opportunity to pass blame, follow manufacturers instructions.

So we have rely on about 8 Turbo screws 25mm to hold on....

 

[charlie1]

So we have rely on about 8 Turbo screws 25mm to hold on....

I don't set the guidelines, I'd guess around 50 screws per board. Yes, it's the screws that hold the boards to the floor, not the adhesive.

 

[White Room]

I don't set the guidelines, I'd guess around 50 screws per board. Yes, it's the screws that hold the boards to the floor, not the adhesive.

More holes than a pin cushion....

 

[2020Tiling]

Might as well use a non flexi slc to fill the voids haha... (joking) don't try this kids!! :yikes:

 

[rj1884]

What do you guys think of plastic ply

 

[Andy Tiler]

What do you guys think of plastic ply

I don't think id trust it purely because there's a plastic sticky back coating that's holding it down???!

 

[The Legend; Phil Hobson RIP]

I don't think id trust it purely because there's a plastic sticky back coating that's holding it down???!

Just seen this I agree with Andy re. plastic ply. As far as the boards go Marmox, Wedi, and the like are no good on floors if the tile is less than 50mmx50mm ie. mosaic, geometrics, due to point loading issues.

 

[johnryan]

What do you guys think of plastic ply

used it once before on new build flats. only used it due to moisture proof flooring, and this was the only thing that i could find that the manufacturer said can go onto that substrate, after being informed by several adhesive tech depts that none of their adhesives can be guaranteed to stick to green chipboard.also, the architects/builders refused to let me raise the floor the 8 or so mm with hardi or marmox. it was very easy to work with, and been 2 years now and no call backs. however was a great worry, and probably wont use it again.