creaking T+G chipboard floorboards

[eduardus]

I have just replaced my old floorboards with new 22mm T+G
floorboards (600x2400 mm).
When I stand on the edge of one floorboard and jolt up and down I can see a slight movement between the boards and it creaks
I thought this would not happen with T+G boards.
The boards are tight together and I used no. 8x2" screws,
drilled a clearance hole and screwed 3 of them in the width
of the board in every joist.
The joist are 18" apart.
Can somebody tell me the reason for the movement and creak
and how to rectify it.

 

[masona]

Either the wallplate has rotted away which hold the floor joists or the floor joists is too far away from the wall area.

 

[eduardus]

Either the wallplate has rotted away which hold the floor joists or the floor joists is too far away from the wall area.

The joists are laying on walls 5 foot apart and the movement is between
one board and the next.

 

[masona]

What measurement are the floor joists in between ? The 5' joists apart are sleeper wall which the floor joists rest on. Can you check for wet/dry rot with a screwdriver (normally very soft on the bottom), if it's soft then this can cause jumpy flooring.

 

[eduardus]

What measurement are the floor joists in between ? The 5' joists apart are sleeper wall which the floor joists rest on. Can you check for wet/dry rot with a screwdriver (normally very soft on the bottom), if it's soft then this can cause jumpy flooring.

The joist are 2"x4" and 18" apart.
The total length is 10 foot and half way they rest on a sleeper wall on a dpc.
The timbers are good and firm.

 

[masona]

Okay, you may need to fit a extra joist nearer to the wall or put in some noggin where it's creaking. Normally the first joist against the wall should be no more than 50mm from the wall.

 

[eduardus]

I put in some noggin, PVA glue and more screws and the
creaking is gone.
Thank you for your help masona.