The original part of the kitchen in concret laid with quarry tiles, when we knock through the pantry to extend the kitchen slightly, the new part is now made up of T&G floorboards.

Ive got some tiles already to put down, what is the best way to go about doing this?

I cant overply as the level is the same and overplying with make the T&G section higher. I guess I could have overplyed and self levelled the rest to match in height, but Ive already fitted the whole kitchen.

What are my options, any of the following work

1. tile straight over with flexible adhesive
2. Remove floorboards and lay 18mm WBP Ply with an expansion gap between concrete and ply and tile over this

Or should I be doing something else?

In my opinion Your 2nd option is the way to go mate. You seem to have done your research.

Shluter do some good expansion joint's, there a forum sponsor you'll find their site at Schluter-Systems UK Homepage +44 (0) 1530 813396 - Schlüter-Systems

Remember that the expansion joint is between tiles, not just substrate mate. And make sure the ply is solid enough, add extra noggings if required. Doing it right first time will be cheaper in the long run.

Schluter also do a ditra matting which you can use with two different surfaces. Stick down with a rubber adhesive and tile with single part flex adhesive on top

Originally Posted by panceramics

Schluter also do a ditra matting which you can use with two different surfaces. Stick down with a rubber adhesive and tile with single part flex adhesive on top

Ditra is an isolating membrane designed to counteract lateral movement of the substrate. it is not suitable for bridging different substrates without an expansion joint.

There are a few options you could consider:

1st: How sound are the floor boards if they are firm and no movement then you could get away with Bal 2 part flex with an expansion joint where the two substrates meet. This would be your cheaper option.

2nd: You could lay 6mm hardie backer board on the floor boards screwed down and then even though you are raising the wooden area by 6mm you could then use Bal PTB adhesive as you could then have thicker bed on your concrete side or if you removed your quarry tiles the hight would work out. Again have a expansion joint where the 2 substrates meet.

Bal PTB allows a bed of 3 - 25mm.

You do not say what size m2 you are tiling or tile type.

Cheers,

Highlander

Hi

Total area is around 6m2, 1m2 is wood floorboards. There seem strong, no creaks.

How does the expansion join work and where can I get BAl 2 part flex from?

Thanks

If I ply out, can I use normal rapidset adhesive and add a flexible additive?

On the same theme - I am installing a wet underfloor heating system and intend to surround it in a fairly dry screed mix and then lay 18mm ply, finally tiling on top of the ply. Do I still need to wait a very long time before I tile, please?