RichardS wrote:
I've just taken delivery of a load of 135x19mm T&G oak floor
planks for the two downstairs reception rooms, and whilst I
finish some other jobs and wait for it to acclimatise I'm
going through the detailed planning for it's installation.

Who supplied it? It may be very dry, in which case you don't need
to let it "acclimatise".

[ ... ]

My plan, therefore, has been modified from my original intention
of screwing & plugging the new floor straight onto the joists
(this seems like a ridiculous amount of work and complete
overkill) and instead installing a WBP ply subfloor & secret
nailing to that, but creating a couple of removable sections
with the boards secret nailed to the ply, but screwing and
plugging those sections through to the joists instead of fixing
them permanently.

I don't like the sound of this *at all*, I'm afraid.


This seems to have a couple of advantages, namely

1) it creates a nice, flat subfloor for easy laying of the new
floor;
2) it means that the boards will be somewhat protected from the
humidity variations in the ventilated cavity and hopefully
prevent cupping and warping;
3) the boards aren;t end matched (t&g each end) as I'd expected,
so I won't have to ensure that joins are above the joists.

However, there are a couple of questions about this...

- is 9mm ply thick enough to nail into, and is it enough to
provide strength for any joins that occur between joists
(they're 14" centres)

14" centres? You will lose minimal material going straight on
to joists. It's only a 12" gap. 9mm ply is *nowhere near*
enough to nail into on its own, you will find lifting problems
& have to re-do.

IIWY I'd lift the old floorboards (may be saleable), fix any
joist/sleeper/dpm/infestation/service problems, and go straight
on the joists. Where you may need access (is the void deep enough
to enter and work?) screw the boards down, removing the under-
tongue of the last.


- when secret nailing, is it necessary to pre-drill? I'm
concerned about nails splitting the tongue.

Depends on the timber and the nail (use square-ended as in
floor brads, not as in wire nails).

If 9mm isn't up to it, then I could just about accomodate 12mm,
but 18mm would be way too thick & I'd have to rethink (again).

I just wouldn't do it. If you really want a vapour barrier,
use pitch paper or even polythene DPM. You might give some
consideration to insulation between the joists, too, such
as jablite.


Oh, whilst I think about it, I'll want a finish to darken the
floor. Wax? Oil? Any suggestions welcomed...

I wouldn't use varnish of any sort, oil first/wax after should
be fine. It will need a polish every litle while, but it's
easier to do this than re-varnish!


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