Following our previous blog post tiling a wooden floor - yes you can! we have been asked several times if it's possible to tile directly onto chipboard flooring. To give a definitive answer about tiling directly onto chipboard or floor boards (tongue and groove) we felt another post was needed.
Can you tile onto chipboard? - the short answer.
Yes - sometimes...
IF your floor is very well screwed down and has little deflection (we recommend the two fat men test*) then some modern adhesives such as granfix ultimateflex can be used.
BUT You have to be honest with yourself about the current state of the substrate, the deflection and stability of the floor. Small bathrooms often suffer less with deflection due to the shorter span.
Chipboard flooring - the problems.
1. Chipboard flooring flexes quite a lot, and often isn't screwed down well, both of these things cause movement and movement is your enemy. The worst kind of movement is deflection; this is where the boards bend down in between the joists, or the joists themselves flex when you walk on them, this is often the reason for cracked tiles.
2. Water damages chipboard, once chipboard gets wet it swells and falls apart, which will lift your tiles. Newer 'green' chipboard is used to help with this but still isn't perfect.
There's nothing at all you can do about chipboards hatred of water, for this reason don't use chip in a wet room or any constantly wet area. However the odd splash from a shower or bath isnt going to hurt.
Tiling Chipboard - Solution 1
The preferred solution for a trouble free floor is to overboard your floor with a backer board called no-more-ply. This is a cement based board that stops movement and also reduces noise transfer.
For details on how to fit no more ply, see this earlier blog post on how to tile a wooden floor.
Tiling Chipboard - Solution 2
If your floor doesn't have excessive movement, you may tile directly onto the floor using Granfix Ultimateflex. This very flexible adhesive will stick to chipboard and will absorb the floor's movements. The reason we warn about floors with excessive movement is the simple fact that tiles don't flex! On a surface with lots of movement, this super adhesive will do its job and cling to the floor, unfortunately your tiles will develop cracks due to the movement.
On a well supported firm floor, screw the boards down every 150mm along each joist, taking care not to puncture pipes or electrics - this will stop the boards moving and help with board (but not joist) deflection. If your floor passes the two fat men test* proceed as follows:
- Abrade\Sand the floor to remove wax, dirt etc - especially with green chipboard.
- Seal the floor using Granfix acrylic bonding agent and allow it to dry.
- Fix your tiles using Granfix Ultimateflex adhesive.
- Grout with Granfix maxigrout flexible in your choice of colour.
What you may need for the job
* Just what is the two fat men test?
It's as simple as it sounds, ask a couple of friends to stand in middle of the floor and bounce up and down, if the floor moves up and down lots (try placing a glass of water on the floor so you can see) then that deflection will cause your tiles to crack. Instead of using the method above over-board your floor with no more ply instead as detailed in this blog post