On 2007-09-25 22:41:53 +0100, "Mark" said:


"Grunff" wrote in message
...
Mark wrote:
I'm planning on laying a t&g oak floor.

The existing floor is concrete and not particulary smooth.

I'm doing my homework first to establish the correct procedure.
Is it similar to laminated flooring with a dpc membrane and soft
underlay boards?
Is it normal to glue the boards to each other?

While it is possible to lay an oak floor as a glued floating floor, it is
not recommended. This is because while laminate behaves in a uniform way
in response to humidity changes, oak expands and contracts non-uniformly.
Depending on how your oak has been sawn, the stresses in a floating oak
floor may result in it coming apart over time.

There are 3 recommended methods for laying an oak floor on concrete:

1. Battens, then secret nailing. This is simple, reliable and always
works. Putting down the battens takes a bit of time, but once they're
down, the nailing is pretty quick (with the correct nailer that is).

2. Double sided adhesive underlay. This is like a 3mm thick stretchy
underlay, with adhesive both sides. You stick the underlay to the floor,
then stick the oak to the underlay. This only works if you have a smooth,
dust-free concrete floor.

3. Instead of using battens, you use lines of special rubbery glue. You
apply these at 30cm spacing, and lay your oak floor onto the glue lines.
The glue remains flexible, allowing movement in the oak floor. This method
can be used on more uneven floors, but the concrete still needs to be dust
free, so you may need to seal it.

For my money, I'd batten with 50 or 75mm battens, and insulate between the
battens with kingspan.


Thanks for this Grunff.

I actually sealed the floor today with diluted PVA as I was fed up with
constantly dust-busting.

Option 1:
I did wonder about this but was concerned about the height rise.
What do you think is the minimum thickness of batten I could get away with?
Are the battens placed loose on the concrete?

Option 2 is out, it's not a smooth screeded floor.
Option 3: Any idea where I might get such a glue?


mark

FWIW...

I have some oak flooring on concrete where method 1 was done. This
is in a relatively modern house (1980s) where the floor is both
screeded and insulated in the concrete already. Therefore Kingspan
wasn't needed, but I think could be interesting where the floor is not
insulated.

The battens are 50x25 nominal and are fitted to the floor with plugs
and screws. Then the boards are secret nailed. I am doubtful that one
could get away with much less thickness than that. The floors have
been in place for about six years and are perfectly fine.

Obviously if the floor is uneven, one would need to pack the battens to
bring them level in both directions and avoid them undulating.