The subject of laying wooden floors has appeared numerous times in he
group with some excellent advice.

Please help......

We would like to install solid oak floor in our kitchen / diner that
has just been knocked through. The dining room is the original
(1900's) wooden board subfloor. The kitchen subfloor is 80% (5m Sq)
concrete and 20% (1.25 m Sq) wooden board.

I have been advised not to glue across different subfloors and will
therefore attempt to nail or float. I have been advised to lay 18mm
ply across the entire floor.

However, despite trying to level the concrete floor once already, it
is still in a bad way, I have variations of up to 5/6mm (it is better
than it was!!). I dont think this is level enough if covered with ply
for either float or nail! Can I get round the variation by laying
battens and pack out the hollows? Is 15mm (suggested in another post)
batons thick enough to nail? Junckers technical info suggest a
minimum of 38mm plus packing - this is too high!! Is this something I
can do myself! I am running over budget and cannot afford to pay for
the installation.

Finally.... do I need underlay? Beneath battens or play (if I manage
to level the concrete enough) If so what type?

Any help appreciated

Many thanks

Simon