Wood floor advice needed.

[volvomanx]

I live in an older bungalow with solid brick walls and a solid concrete floor.
I need to improve the heatloss problem and I am going to insulate the floor.
I know this will raise the floor level but I can deal with this.
My intention is to remove the screed, to reduce the overall height added, and self level with compound. Then I want to lay Celotex/Kingspan type insulation before laying the wood T&G type boards.
I had intended to lay chip board over first then the flooring but noted that 'Woody' recommends plywood under if nail fixing.
Do I have to nail fix or can both the plywood and the floor boards float.
The other way I thought of was to lay a thin thermal break celotex on the concrete, batten over this with (stainless steel fixing into the concrete). lay more insulation between the battens the fix the floor boards to the battens.
I prefer the float option but will be grateful for any advice given.
Also, I am aware that I will need a vapour barrier and underlay.
The room is 12x12 feet with a bay window. I expect the floor will be about 3 inches higher when finished.
Thanks for reading.
Regards, volvomanx

 

[AronSearle]

You could float some T&G chipboard down (gluing the joints together), then float another wood T&G board over that, I would not recommend floating solid hardwood (that should be nailed), but an engineered board, preferably with a clip system.

The screed will need to decently level, and you will want to put slip membranes between each layer to avoid any squeaks.

 

[volvomanx]

Thanks for the prompt reply AronSearle
Your advice sounds good to me and I'm happy to do that. Just to be clear though, if I was to use a hardwood board, can I use a plywood base and nail into that. I know I would not be able to glue in the same way as chipboard.
Regards,volvomanx.

 

[AronSearle]

Yes, if you use a hardwood floorboard, you can nail into plywood, I would recommend 18mm+ thickness.

 

[volvomanx]

Thanks again AronSearle.
The missus will have the final say over finish, but I will know now how to proceed.
Regards, volvomanx