Set up currently is that I have a floor with 2/3 floorboards onto joists and 1/3 concreter at the same height of the floorboards.
I want to lay a new wooden floor but need to raise the height of the main section to run the new/reclaimed floorboards right across the whole room.
My thinking is as follows:
1. small battons on the concrete to nail the new floorboards.
2. Raise the footings of the joists to the correct level then just lay the new boards over the lot
or
2. Leave the joists footings in place and raise the height of the joists by screwing in battons on the top of them.

I don’t want to dig out the concrete section to lover that end as it has a DPM and I don’t want to disturb it.

Any advice/tips would be most welcome.

If the exisitng floorboards are the height you want the joists to be can you not just leave them on instead of applying batons?

I’m not a flooring fitter but I’d try and ‘float’ a floor over the existing wooden floor and concrete rather than trying to attach to it – it’s all going to expand and contract at different rates underneath.

Break out the concrete floor and run the new floor at the same level as the existing floor. It’s the best option long term.

This will avoid any changes in level between this room and the rest of the building.

You need to consider the knock on effect of raising the floor level.
You’ll need to replace all the skirtings and door facings.
The door apertures into the room will be reduced in size which might make getting furniture in and out of the room a royal PITA. Window cill heights might not meet the minimum required for building regs. Sockets and switches will be at the wrong levels.

Sockets and switches are all being changed so that’s not an issue as the whole room is being replastered.

The issue I am concerned about re digging up the old floor is the damp proff membraine there that would have to be removed along with the 1/2 tonne of rubble as well! I would imagine I would need another DPM and relay concrete after all the excavation.

I had though about just laying the new floor over the old but was converned re creaks. I might give this another thought though.