On Tue, 20 Dec 2005 15:58:24 +0000, Séan Connolly wrote:

http://tinyurl.com/byg2v

If the unevenness is of the order of 1-2mm no need, that stuff is fairly
thick and will absorb minor irregularities, especially slight steps
between floor panels/boards. You could add a course of the 2mm foam
underlay too if needed - tack it down with a staple gun. Leave small gaps
(1-2mm) betweeen the green slabs. Not critical but this stuff does expand
and contract too, basically don't pack it tight in.

Do check that you haven't got any major undulations or low/high spots with
a 2-3 metre straightedge on the subfloor before you start:

I didn't and I had to insert packing around a doorway after the fact
which worked out OK, but less than perfect - if I'd noticed I'd have
considered levelling compound first. This was due to a floating floor
where the chipboard was sitting on expanded plastic slabs which had
compressed over the decade around most doorways. The depression was about
5mm-7mm over a metre or so, not enough to see, but enough to form a hollow
under the laminate. Laminate can follow gentle undulations, but not that
extreme.

Have I ever said that some modern building practises are the work of the
devil? Floating subfloors and drywalls - lazy, cheap and evil.

HTH

Tim