Hi all, I have a large area of concete floor I want to cover with
standard pressed/composite wood flooring, size is 9.5 M x 10.5 M. I
dont really want to have the hassle of laying down joists etc, so I
wondered if I bought this stuff at srewfix
http://www.screwfix.com/app/sfd/cat/...65020&id=52649
(I need the DPM because the floor may be slightly damp) and put it
down, could I lay the moisture resistant 4'x8' tounge & groove standard
1/2 inch wooden composite wood boards over this (and glue them in the
joints) and create a large floating floor ? I am hoping the weight of
the floor itself will create its own ridigidity and stability. Is this
plan silly or viable - thanks for any help.

The message .com
from "pantsy" contains these words:

I am hoping the weight of
the floor itself will create its own ridigidity and stability. Is this
plan silly or viable - thanks for any help.

I can't see why it shouldn't work, but don't forget to leave space round
the edges for thermal expansion - which might be quite considerable over
such an area. What's "composite wood boards"? Do you mean ply or OSB, or
MDF or what?

--
Skipweasel
Pay no attention to that man behind the curtain.

pantsy wrote:
Hi all, I have a large area of concete floor I want to cover with
standard pressed/composite wood flooring, size is 9.5 M x 10.5 M. I
dont really want to have the hassle of laying down joists etc, so I
wondered if I bought this stuff at srewfix
http://www.screwfix.com/app/sfd/cat/...65020&id=52649
(I need the DPM because the floor may be slightly damp) and put it
down, could I lay the moisture resistant 4'x8' tounge & groove standard
1/2 inch wooden composite wood boards over this (and glue them in the
joints) and create a large floating floor ? I am hoping the weight of
the floor itself will create its own ridigidity and stability. Is this
plan silly or viable - thanks for any help.

Leave about 1/4" round the edge, for exapansion.

The foam does not remove the need to get the floor pretty much dead
level though.

"pantsy" wrote in message
oups.com...
Hi all, I have a large area of concete floor I want to cover with
standard pressed/composite wood flooring, size is 9.5 M x 10.5 M. I
dont really want to have the hassle of laying down joists etc, so I
wondered if I bought this stuff at srewfix
http://www.screwfix.com/app/sfd/cat/...65020&id=52649
(I need the DPM because the floor may be slightly damp) and put it
down, could I lay the moisture resistant 4'x8' tounge & groove standard
1/2 inch wooden composite wood boards over this (and glue them in the
joints) and create a large floating floor ? I am hoping the weight of
the floor itself will create its own ridigidity and stability. Is this
plan silly or viable - thanks for any help.

While it is needed under thin laminates, if you are laying flooring quality
chipboard, I'm not sure that the foam layer will do much. It would be
cheaper to use an plain DPM. Otherwise, it should work, but, as Guy says, do
make adequate allowance for thermal expansion around the edges. Laminate
floors usually suggest 10mm all around, but, over that area, I would
probably double that.

You will in any case need to lift any skirting boards, to allow for the
thickness of the chipboard, so you could simply fit thicker boards to cover
the gap. It would probably also be a good idea to wrap the DPM up behind
them, to protect them from damp too. If you plan to put carpet down over the
floor, a vertical gap under the skirting boards allows the edges to be
tucked under it.

You will need to devise a way to apply pressure to the edges of the boards,
so that you can get the joints closed tightly. Normally you would use
floorboard cramps, which grip the joist, but that will be difficult without
any joists. Perhaps horizontal Acro props would work, but remember to put
temporary packing pieces between the wall and the first boards in, to
maintain the expansion gap. Also, remember that it is important which side
of the boards is up. The T&G is cut so that there is a small gap on the
underside when the top edges are closed tight.

Colin Bignell

On Thu, 30 Mar 2006 08:14:06 +0100, "nightjar" nightjar@insert my
surname here.uk.com wrote:

It would be
cheaper to use an plain DPM.

John Prescott?

:-)
--
Frank Erskine

The message
from "nightjar" nightjar@insert my surname here.uk.com contains
these words:

You will in any case need to lift any skirting boards, to allow for the
thickness of the chipboard, so you could simply fit thicker boards to cover
the gap.

So much better than nasty beading all round the floor.

--
Skipweasel
Pay no attention to that man behind the curtain.

Great replies all thanks- the floor is actually the base of a large
metal (insulated ) shed, I appreciate the advice about the materials at
screw fix. And yes I mean floor quality moisture resistant chipboard
with T&G. I was concerned about heat loss through the floor into the
concrete -as I live in Northern Scotland & its colder for longer up
here !!!! But it sounds as if you guys think the wood may be enough of
an insulator without the foam & just a standard dpm ? My local builders
merchants has the option of 18 or 22 mm boards - so it may be easier &
cheaper to get the thicker boards & not bother with foam insulation? At
least thats what I am taking from the aswers so fat.

pantsy wrote:
Great replies all thanks- the floor is actually the base of a large
metal (insulated ) shed, I appreciate the advice about the materials at
screw fix. And yes I mean floor quality moisture resistant chipboard
with T&G. I was concerned about heat loss through the floor into the
concrete -as I live in Northern Scotland & its colder for longer up
here !!!! But it sounds as if you guys think the wood may be enough of
an insulator without the foam & just a standard dpm ? My local builders
merchants has the option of 18 or 22 mm boards - so it may be easier &
cheaper to get the thicker boards & not bother with foam insulation? At
least thats what I am taking from the aswers so fat.

What loads are you putting on the floor? How good (what) is the
rest of the insulation? Draughts? Heating?

difficult to say about loadings - I am going to convert it to a photo
studio for my own use at present- but possibly in the future (planning
permission allowing) I might open it up to have more people in there -
up to 11 at a time say. In one corner I plan to have an office and a
dark room - about 3.5 m x 4 m so will be building this out of
plasterbaord & wood etc, but the majority of the load for that will be
taken up on metal pillars inside the building I can attach to. The
metal sheeting itself has 60mm composite insulation sandwiched between
2 steel sheets, so is quality stuff !! it's been well built & pretty
well much sealed like a industrial work unit with no draughts. Its
only going to be people and photo equipment no - cars or anything like
that will be in it. I am hoping to heat this with oil radiators or get
hold of some storage heaters.

pantsy wrote:
it's been well built & pretty well much sealed like a industrial work
unit with no draughts. Its only going to be people and photo equipment
no - cars or anything like that will be in it. I am hoping to heat this
with oil radiators or get hold of some storage heaters.

I should do a job on it, then - it won't be *that* expensive. Cost up
50mm battens, Jablite, and 22mm Caberfloor. It's quite big (it sounds
as though you've at least 7m x 8m) and it'll take a bit to heat, so
you might as well have a reasonable floor!

pantsy wrote:

(I need the DPM because the floor may be slightly damp)

I have a concrete floor which used to get damp after heavy rain
even though there was a DPM underneath and a drain around the edge.
I found some paint which is basically like cement with a rubber
compound in it. This completely stopped the damp coming through.
I have no idea of the name of the product and it's bound to have
a different name in your country.

I think you are Probably right Chris, how widely spaced should the
battens be? I assume if I am putting battens down I can just nail the
T&G Caberfoor to them and not worry about cramps etc whilst they are
glueing ?