"brugnospamsia" wrote in message
. uk...

Not quite. I thought you said you had the floor up and so I would run
the
Airtec over the top of the Kingspan and over the top of the joists so
that
before you lay the floor all you can see is Airtec.

If the floor has been fitted then you could instead run the Airtec under
the
bottom of the joists as well as under or on top of the Kingspan. The
problem with this method is moisture could be retained against the
joists
so
you need to build in some slack so that any condensation drains away
from
the joists, not towards them.

Either way gives you want one continuous run across all the joists, then
taped up in parallel to give a complete impervious sheet.

yes, the floor will be up, I just had the feeling I ought to leave the
joists room to breathe - so a porous membrane with bulky lagging felt
right - also less thickness of material under the boards ...

They breathe in the area under the floor - which is what they were designed
to do of course.
The Airtec will squash almost flat between floor and joists.


Having just done a couple of ceilings with dry-lining screws, and having a
nice new drill/driver to play with I'm wondering if there's a nice way to
use japanned screws for floorboards ... no doubt I would have to
countersink, plug the holes with dowel and chisel them flush as I would if
I
was making a boat ... shipshape and Bristol fashion .... ?

If they are nice floorboards you want to have on show then use blind nails.
These are nailed through the tongue such that the groove of the next one can
still fit home tightly. You'll also need tho hire the special tool to
compress them together properly.