Tiling Question

Should i use additional wooden board to tile on, in a upstairs bathroom ?

Instead of tiling straight onto the original wooden flooring boards. Should an additional wooden board be used to tile on ? Also are the any special adhesives I should use to waterproof it as well ?

11 Answers

Best Answer

Come on,i thought we were all supposed to be professionals on here!

I'm not a tiler but even i know you should NEVER pva plywood,all the good tiling adhesive manufacturers will tell you this as well.

To seal plywood properly,you need to use a latex based primer/sealer,NOT water-based PolyVinylAcetate and then a cement based flexible adhesive & grout for your tiles.(not ready-mixed,powdered you mix yourself.)


Answered 17th Apr 2011

carl melady

Member since 1 Jun 2008

hi you can tile straight onto floorboards if there fixed securely and level with a special flexible floor adhesive for floorboards,but really i would advise to get some sheets of ply at least about 5mm and screw this over the floorboards use plenty of screws or otherwise the ply will bow, but make sure screws are not to long as you dont want to pop any pipes under floor ..then seal the ply with a p.v.a and then use a flexible floor adhesive to fix tiles and a flexible grout ..this will allow for any movement or shrinkage ,,,as easy as that ..good luck

Answered 16th Apr 2011


Member since 30 Sep 2008

Hi, yes you will need to put a sheet of ply down on top of the existing floor baords as this will strenghten the floor up and prevent it form moving, which will then stop the tiles from moving and coming away.
you can use 4 mm ply, but i would use at least 6mm as this will be stronger, but when you lay it, it doesn't have to be 100% perfect to the edge of the walls and is best to leave about a 10mm gap all the way around between the edge of the ply and the wall.
when fixing it down, i would use screws no longer than 20mm as you could be in danger of hitting pipe work below and make sure you put loads of screws in, i.e 1 screw about every 15 cms apart all over the floor as this will stop the baords from bulging in any areas making the tiles come loose. more screws the better.
make sure you buy flexible floor adhesive as this will help with any movement that the floor has, as there will always be some movement.
hope this helps.

Answered 16th Apr 2011

D.J.P Carpentry Services

Member since 4 Mar 2011


Answered 16th Apr 2011

R.J Gurney

Member since 27 Jan 2010

if you can use 19mm ply screwed to the joist and use flexible adhesive and grout good luck

Answered 16th Apr 2011

Dartnote Ltd

Member since 2 Nov 2010

Hi There, If you are putting ceramic tiles onto a traditional wooden floor board then you must use plywood to cover the floorboards. Use a 5.5 or 6mm ply depending on what is available in your area, either screw down using nickel or coated screws (20-30mm) or galvanised nails. Please dont nail down with bright nails as they rust and the rust pops the tiles. Seal the plywood with pva. Then tile using a flexible tile adhesive (powder from bag and mix yourself) You can get adhesive and latex if you are worried that there will still be movement, again use a flexible grout to finish.
regards mark

Answered 16th Apr 2011

Pro Finishing Services

Member since 12 Jan 2010

Tiles should always be fixed onto a water proof plywood decking. If oiginal floor boards are sound, then a 12.5mm plywood should be screwed down before tiling commences. If possible, take out floor boards, install 18mm WBP plywood and screw down using 50mm high tread screws. Must then use rapid set, flexible tile adhesive for the best result

Answered 16th Apr 2011

white cliff bulding solutions

Member since 26 Dec 2010

No feedback

I think that this would depend on how level your boards are, otherwise you will have to use a lot of adhesive to get the tiles level,regards Terry.

Answered 16th Apr 2011

tm property services

Member since 9 Mar 2011

Hi you will need to use exterior ply on the floor(min 6mm)you then need to make sure that you use a flexible adhesive an grout.

Answered 16th Apr 2011


Member since 20 Feb 2010

hi there u need to put concret play on the wooden bord and then u can tile , or take off the wooden board and replace with 15mil mdf , u need to use flexsible adhesive . thanks and gd luck

Answered 16th Apr 2011

Esam & Son

Member since 12 Jul 2010

try useing ply board and screw it to the floor boards you can get waterproof adhesives as well

Answered 16th Apr 2011


Member since 7 Feb 2009

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