Timber to screed with limestone - Tile Advice

[faceman]

I’ve got a timber to concrete floor to do. I haven’t done one for ages and when I did it was on the request of the builder so the responsibility was on him. This one though is for an old couple who have picked a 20mm limestone to be laid random bond across the joint so I don’t have the luxury of a cold expansion joint on the edge of the tile. I viewed it this morning and my theory was to hardibackert the lot and glue screw the wood end with a board bridging the joint. I know people on here will be screaming expansion joint, expansion joint but can I not?

 

[J Sid]

Turn the bond the other way and put in expansion joint.
What you bridge the area with could and very likely fail

 

[Time's Ran Out]

Doubt if anyone could speculate on the amount expansion of an unseen joint!
I would suggest you consider an uncoupling layer for Stone whatever substrate preparation you decide on.

 

[faceman]

I’ve talked them into turning the bond and it works out lovely on the end of a tile where the timber meets screed. My idea is Hardi backer the timber and lay durabase over the 2 Screeder parts (one being the 2nd extension). I will then taper the level change from board to mat. My next question is how far past the timber would be advisable before starting the durabase?