DIY Related: Tiling over floorboads in a bathroom

[aled]

Hi,
I am renovating my property and the bathroom needs a complete overhal. At the moment the bathroom has floorboards. I am not happy to simply tile onto the floorboards as there could be some movement with them. So, with this in mind i need to make the floor more rigid before tiling. Should I: -

1. Fix plywood on top of the floorboards. I have read that to do this i need to use 12mm WBP plywood screwed every 150mm. The only issue with this is that it could cause a step from the landing into the bathroom. Something I would like to avoid if at all possible.
   
2. Remove the existing floorboards and fix plywood directly onto the joists with 25mm WBP plywood fixing noggins where boards join across joists.

I am not in the trade and I have no idea what I exactly need to use in order to make the floor ready for tiling. I would be grateful for your help and advice.

Thanks in advance

[CJ CERAMICS]

hello aled and welcome to the forum.

both of your options are the correct way but the better of the 2 is to remove the floorboards and replace with wbp plywood.
you will have to check as to where the joists sit as to your walls as you usually find that the wall sits bang on a joist if this is the case you will have to add another joist or 2 so that you do not have any movement. as you say extra noggins will be needed where boards join. personally i also add noggins every 2 foot for added strength. you will need to prime the underside of the plywood to stop moisture penetrating from below. once the plyborad is down you would be best to overlay this with 6mm hardibacker to give a better tiling substrate.

hope this helps
chris

[aled]

Thanks Chris,
If as advised I should put 6mm hardibacker on top of the wbp plywood does this mean that I can go for a thinner board instead of the 25mm?

Thanks
Aled

[CJ CERAMICS]

i would not go any less than 22mm personally aled but that is just me, some of the other lads may use different sizes but i would wait until later today to see what responces they give. You may have to check back later this evening as most of them will be working at the mo, and wont be online until later.

chris

[peckers]

what size room is it and what tiles are you using? the above advice is good advice

[aled]

The floor area is 1.78m x 2.60m. We will probably be using a ceramin tile as seen at the following link

[Sir Ramic]

Remove old boards and replace with 22 wbp ply. Then 6mm backerboard. This will give you no more difference in height than by over laying with 12mm as stated...12mm is too thin anyway.
While the floor is removed you may as well add some noggins for extra strength. You only want to do the job once, so do it well.

[Bri]

Welcome along

[whitebeam]

Hi and welcome

[Dave]

Remove old boards and replace with 22 wbp ply. Then 6mm backerboard. This will give you no more difference in height than by over laying with 12mm as stated...12mm is too thin anyway.
While the floor is removed you may as well add some noggins for extra strength. You only want to do the job once, so do it well.

I concur with this reply..

[aled]

Thanks for the advice. How do I attach the backerboard to the wbp ply? The ply will be screwed into the joists so how is the backerboard attached to the ply? Is this again through the ply and into the joists? Or is there a different way of attaching this?

[Dave]

You apply a 4mm bed of flexible adhesive then 25mm screws will be fine to screw through the hardi into the ply.. the reason behind the hardi over the ply is that is is a more stable substrate to tile to..

[dilz000]

good advice as always

[davebates]

hi and welcome im new too

[blocko]

What expansion gap do you all normally leave between each board? I have been leaving a 5mm expansion gap to be safe, just wondering what is deemed the best really.

[doug boardley]

What expansion gap do you all normally leave between each board? I have been leaving a 5mm expansion gap to be safe, just wondering what is deemed the best really.

I leave about 2mm Blocko

[blocko]

I leave about 2mm Blocko

Ok thanks Doug, thought I was OTT with 5mm. Will keep it down from now on!

[Perfect Tiling]

I normally leave a 2-3mm gap which is then mesh taped over, filled with adhesive and levelled off...just like plasterboard. Also best to stagger your boards and put them down in the opposite way to which the floor boards or chipboard go. Not always possible and if its only a small room then not always necessary.

[aled]

I will be using 25mm wbp ply on the floor. I know i need self counter sinking screws but was wondering which ones were bast to get (name and size)

[dilz000]

Aled you need to overboard the ply with backerboard too.

Well you don't need to, but it is highly recommended