Plywood Vs Hardiebacker

[Bathfix Bob]

There seems to be a quite a hate campain against poor old plywood lately, so much so that I think I'll take on board the advice and start using 6mm Hardiebacker on my bathroom floors now from now on. Most of my bathrooms are only small to medium.

Can someone please tell me the correct procedure for these, eg screw or bond, prime one side, both sides or none expansion gap between boards etc.

I just don't want to do anything wrong, I've only just started reading this priming the underside on ply business, none of mine were primed underneath, only on top.

One last question though, surely the overall strength of the floor will be better with 18mm ply screwed down rather than 6mm cement boards? I thought the whole point was to 'beef up' the floor rather than provide a better surface for tiles to actually stick to?

 

[thomas]

i still use the plywood on floors and bath surrounds,never any trouble in 15 years,once its fitted correctly,whats the price difference between ply and hardiebacker?

 

[Scott]

You are right 18mm ply will make the floor stronger than a cement board. The purpose of the cement boards is to provide a more suitable surface to tile to and not to strenghten the floor. Although as you are adding a laminate to the exisitng floor it must aid the strength in some way but not as much as a ply overlay.

If your floor has any deflection then it will need either more noggins or the addition of a ply overlay to strenghten it. You can then add the backer boards to that to make the surface more suitable.

There is a never ending debate on tiling onto ply, its deemed as not suitable and there are those, of which i am one who have been doing it for years without a problem.

As for sealing the backs and edges this should be done in all situations, Warm Up ufh even have it on thier fitting instructions. As for priing the face, that will depend on whos adhesive you are using, Ultra insist on it whereas other wont.

 

[aph257]

i don't think you can compare them directly. i use No More Ply (hardi is not the only cement board) in situations where existing floor is flex free and strong enough to tile on. if not then rip existing out and fit 18mm ply. i wouldn't use a 12mm ply ontop of floorboards.

 

[YourTiler]

I still use plywood providing the sub floor is sound. If it's not I generally replace any boards that need it or if it's really bad - take it all out and use 18mm or 25mm plywood
Plenty of screws
Not had any call backs to go to

I think it's all about one's own choice as to what to do. There is more than one solution to it and we all have one that suits us most

Each to their own I think

 

[DHTiling]

Hi BB..
Here are some pdf's for you to read..


View attachment 20394

View attachment HardieBacker EN installation 200810 masonry walls.pdf

Hardibacker Cement Backerboard Installation Instructions

 

[andy8758]

There seems to be a quite a hate campain against poor old plywood lately, so much so that I think I'll take on board the advice and start using 6mm Hardiebacker on my bathroom floors now from now on. /QUOTE]

I dont think it is quite a hate campaign yet Bob! I guess the pro ply tend to be longer established tilers - they learnt using it and it works well for them. Many recently trained tilers tend to use modern tile backer boards of various kinds. Personally I use Hardibacker 250 on all wood floors, screwed with 4mm x 16mm screwed at 200mm intervals. That works best for me, but I respect the plywood fans views.