Floor construction in new extension...

[Sylar]

Bit of a tricky one here and looking for the best way to move forward. I'll get started with the scenario....

In-laws have a new rear extension kitchen/diner going in. Rear wall of house removed to create one big space. New extension is block and beam construction, currently approx 200mm below finished floor height for insulation and water UFH. Old kitchen and dining room is suspended timber floor. Floor finish is to be tiled throughout.

We have decided completing the UFH throughout the entire space is probably too complicated to bother with(?) as its spanning two different floor constructions, so we are laying this in the new extension only.

Question is, how do we build the floor construction to finished surface? We have minimal height to play with on the existing suspended floor, say maybe 30mm from the joists to match the hallway.

The concerns i have are keeping the finished level to a minimum in order to avoid a step at the hallway, and cracking of tiles at the threshold of UFH concrete base and non-UFH suspended floor.

Thoughts on best way to commence?

Thanks in advance!!

 

[freddiemercurystwin]

To get the levels to match you work down from finished floor level which will give you your b/b level. I would incorporate a movement joint where the two floors meet.