Tiling bathroom floor- floorboards/cement board question

[Bbbecca7]

Hi all!

Since everyone was so helpful with near tiling disaster last time I am hoping to get a bit more advice now that we are coming to tile our bathroom floor.

We want to make sure we do it right first time!

The floor of the bathroom is wood floorboards. They're in relatively good nick and we will be putting extra screws and supports where needed to ensure there is no movement.
After this we have bought 12mm cement board to be secured on top.. my main question is:

Do we need to use an adhesive to secure the cement boards to the wooden floor boards or can we just screw these down at the advised 150mm intervals. If so, can we use the same flexible adhesive as we would be using to secure the tiles to the cement board?

Also which screws are best for screwing the cement board down?

Then we will be using the flexible adhesive to tile on top of the cement board.

We are way behind schedule so a local handy man is prepping the floor and his tiler will be tiling it but we are supplying the materials.

Thaaaaanks!

 

[Spare Tool]

Prime floorboards, 6mm troweled bed of flexible adhesive, fix boards staggered, 30mmx4mm turbo gold screws, tape joints and skim over tape with same flexible adhesive and your good to go..

 

[Bbbecca7]

Prime floorboards, 6mm troweled bed of flexible adhesive, fix boards staggered, 30mmx4mm turbo gold screws, tape joints and skim over tape with same flexible adhesive and your good to go..

Thanks Andy!
Perfect answer exactly what I was looking for. What should I prime the floor boards with? thanks!

 

[Spare Tool]

Thanks Andy!
Perfect answer exactly what I was looking for. What should I prime the floor boards with? thanks!

No probs...use the same brand of primer as your adhesive manufacturers, diluted as it says on the bottle, generally 3-1 but check the bottle..

 

[Stu Lilley]

Always follow the manufacturers installation instructions for cement boards... we use no more ply and for your job you would need only 6mm pre primed cement boards fixed with mega strength adhesive and 8 screws per board.

 

[Time's Ran Out]

OP has already bought 12mm tile backer boards.
Just a wipe with a damp sponge is sufficient.