Floorboards on concrete?

[DJFish]

Chaps,
Can I please ask your advice?

This is my pristine hallway.
The old boards are nailed to timbers, the first concrete section is the old doorstep and the bit nearest the door is a poured slab from when the porch was extended.
Now the wife has decided that we're having Victorian tiles throughout so we'll be having 'No More Ply' screwed to the boards, but to bring the concrete to the same level as the boards I'm having to lay new 18mm boards directly onto the concrete as shown.

Do I need to lay or paint damp protection?

And is is best to screw or glue or both?

Would appreciate advice as I've never done this before,
Cheers,
Dave

[Silver993tt]

I would lay a damp proof membrane on the concrete before laying the wood.

[XG332]

[m4ckg]

I'd lay 18mm ply pluged and screwed every 6" to the floor then ply over all the with 6mm ply and then tile. Don't tile straight onto the original flooring and make sure it is a flexi adhesive where you have the timber floor