Chipboard floor: my screws are loose!

[RigidRaider]

We have the house owner's nightmare, T&G chipboard floors. 8 months ago I fixed the floor down with 40mm screws after doing plumbing work. Had to take a board up yesterday for access and I was dismayed at how easily the screws came out.

We have noticed that the floor, which was almost silent after we screwed it down, has begun creaking again in recent months. I'm pretty sure the screws are slowly working loose with movement, probably because chipboard is so compressible.

Is there any solution to the irritating problem of creaky chipboard floors?

 

[gcol]

What size of screws did you use 40mm by what? 4 or 5?
Personally I use 50mm x 5mm. If you used 40 x 4 then I'd change em for bigger ones.

 

[RigidRaider]

Thanks! Is the second measurement the pitch or the width?

I'll take your advice and go for bigger when I replace tonight.

 

[masona]

The screw length should be 3 x the thickness of the chipboard.

 

[splinter]

and use screws with a course thread

 

[gcol]

Thanks! Is the second measurement the pitch or the width?

I'll take your advice and go for bigger when I replace tonight.

Diameter of the thread.