Wood and cement floor

[sophiejazz]

I'm tiling a floor that's half floorboard and half cement. Can I cover both straight over with 9mm ply?
Many thanks

 

[Richard C]

I'm tiling a floor that's half floorboard and half cement. Can I cover both straight over with 9mm ply?
Many thanks

9mm isn’t sufficient for over boarding suspended floors. 15mm is the minimum BS recommendation & which all adhesive manufacturers recommend but 12.5mm is generally regarded as sufficient in most cases except the most heavily loaded & traffic areas (e.g. kitchen/diners) & it must be WBP not ordinary ply. You need to be very careful where the concrete/suspended floors meet, a decoupling membrane or even a flexible joint is usually required or it will crack.

 

[sophiejazz]

Many thanks Richard, Does the decoupling membrane go over both the wood floor boards and concrete? Or what would be used for a flexible joint?

I'm tiling a floor that's half floorboard and half cement. Can I cover both straight over with 9mm ply?
Many thanks

9mm isn’t sufficient for over boarding suspended floors. 15mm is the minimum BS recommendation & which all adhesive manufacturers recommend but 12.5mm is generally regarded as sufficient in most cases except the most heavily loaded & traffic areas (e.g. kitchen/diners) & it must be WBP not ordinary ply. You need to be very careful where the concrete/suspended floors meet, a decoupling membrane or even a flexible joint is usually required or it will crack.

 

[Richard C]

A decoupling membrane must be fitted over the entire surface.
http://www.tilefixdirect.com/product/SHDITRA1M.html
Its function is to accommodate any lateral movement in the floor without cracking the tiles. It will not accommodate vertical movement due to expansion & contraction of different floor materials.

These are flexible expansion/movement joints;
http://www.schluter.co.uk/movement_joints.aspx
the one you would use will depend on your application.