Connect existing floor to extension (different level)

[oscar3]

Extension floor is 9mm lower than the existing floor (as per pictures).

What's the best way to bridge the gap?

I was considering building a timber frame to support floorboards that would gently slope down to the extension floor. I think it would be better to have it sloping rather than a small step. Any suggestions?

 

[blup]

Threshold strips are available for different floor levels. Don’t forget the finished floor level will be higher so you may be able to use underlay and/or the thickness of the new carpet/laminate to “level up” one or both rooms.

Blup

 

[^woody^]

Add 9mm board to the whole extension floor?

Or just fit some timbers on an angle next to those existing ones. Fit them first and then cut the tops of those protruding ones flush.

Don't even think about forming small step with a threshold strip