I just bought some 3mm 610mm x 1220mm hardboard to lay
over the
floorboards in one of the bedrooms as they are a bit
uneven. I have
searched the web to find what is the best way to lay them
but there is so
many people saying to do it all different ways. I have
seen lay the smooth
side up and then someone else said lay the rough side up,
then i seen lay
it the same way as the floorboards and then someone else
said lay it
opposite way to the floorboards. As i heard you say about
putting down
hardboard on qvc could you tell how much water do i need
to use on each
board then when i wet the boards do i need to lay them
flat to dry out or
do i need to nail the boards down when they are wet and
also do i put them
rough side up or smooth up as i will be only fitting a
carpet with no
underlay.

joe, July 2008

my suggestion:
smooth side up laid in opposite directions to the floor boards

rodney, November 2008

You'll get a thousand answr's to this one.Me?1st,self leveling compound on floorboards,mixed on the thick side and screeded to the worst bits(this will somewhat fill voids)then ply layed across the boards(floor moves,so will ply so this will help to stabalise.)All wood shrinks and expands in reaction to air moisture content,so I wouldn't glue ply down.Nailed,it will still permit floor to move under the ply.Then i'd seal all seams with carpet fitters tape for underlay.This will stop the ply telegraphing the seams through the carpet and becoming visable.Dont forget to leave 10mm of edge/wall gap all the way round to allow for expansion of the ply.if floor that bad then consider fitting 5/8 ply over the whole thing.may solve more problems in long run.

caine, July 2008