Levelling a chipboad floor for laminate - help!

I'm about to lay a lamintae floor in a long room - almost 8m by 3m.

The room was created by adding a partial house extension about 6 years ago and has a floating chipboard floor. The floor is sound in that there are no 'steps' between the boards and therefore appears flat. However, close inspection reveals a 'crest' hlafway down the room. One half of the room appears to be slightly higher than the other. The chipborad the falls away before leveling towarsds the other end. In short it appears that the orignal room is slightly lower than the extension part. I would guess the difference in height between the two rooms is about 15 - 20 mm, the transition taking place over 2 to 3 metres in distance.

This appears to be beyond the recomended tolerance of what is considered a 'flat' floor.

Question is what do I do about it?

What appeared tobe a relatively simple job of laying the laminate is now looking not quite so simple. I have perchased some accoustic deadening underlay from Quickstep (2 mm thick). Would the 7mm fibre board underlay compensate better?

If I go ahead and lay on this floor what sort of problems will it create? My main worry is if the gaps between the laminate 'open' as a result of the uneven floor and then then laminate begins the chip away at the edge.

Is there is straight forward way of leveling the floor without ripping the whole thing up and starting again. To my knowledge the chipborad is laid straightonto polystyrene insulating blocks about 2 inches think which in turn lay on the a comcrete floor.

Any thought/suggestions would be most helpful. Thanks

Geoff

Reply to
Geoff
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I'd use a straightedge (about 2.4 m should be long enough) to get an idea of where the high/low spots are and how gradual the fall is etc. You could try a self levelling screed to even things out. Chipboard is not the ideal surface for it but, sealed with pva, it should take ok. You can't alter the fall but you can make it smoother and get rid of obvious ridges. 20mm over 3 metres doesn't sound like too much of a problem

Reply to
Stuart Noble

Our lounge/kitchen/diner was knocked about to make an open plan affai.

12m x 4m There are 3 distinct "steps" to the floor each step being perfetly flat across the joists. the steps occur on a joist basis so 1 third was level, next third was at least 8 to 10 mm higher from there it was level until the next step.

All I could do was chipboard over the lot and hope the laminated wood floor would make up for what the chipboard left behind.

the wood floor I used is engineered wood "khars" which locks together the same as mdf laminate.

The chipboard and flooring (no underlay worth mentioning) have evened out the steps almost completely you might need to chase a marble across the floor, but that's the only way you'd know.

I think you'll find as long as the hump has been evened out by the chipboard your laminate will cover without any problem.

On ours I did lay the boards 90 degrees to the chip board, so parallel to the offending joists below. This was for aesthetic purposes more than anything, but may well have helped having a joint every 8" in the same plane as the problem. If that makes sense.

Pete

Reply to
PeTe33

Id actually use very thin battens, to lay out a dead level grid, and fill the rest with levelling compound.

Ive used Kahrs here, and you DO notice even minor slopes and bumps. The good news is that waht goes under it doesn't get a lot of stress.

Reply to
The Natural Philosopher

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