Creaking floor problem.

[Manks]

Hi All

We have just had a new extension which has an upper floor supported with 2.5" x 6" joists at 400 centres. The span is about 10-12ft.

Initially we had chipboard flooring and it creaked, so I asked the builder to lay 1" T&G softwood. Initially things were better, but now the creaking is as bad as it was before.

I am reluctant to take up the floor again, but the creaking is driving me nuts.

Does anyone have any ideas what causing the problem please?

Manks

 

[masona]

Did the builder use a Herringbone or solid noggings in between the joists?

 

[Manks]

Masona

I am not sure that he used noggins at all. If he did they would be solid.

If he did not use noggins would that explain it?

Manks

 

[masona]

Can do, if there's no noggins then each joists will bow slightly wherever you're walking on each joists or loose joists in the walls etc

 

[Manks]

This is interesting. I need to find out, don't I?

 

[and1c]

This is interesting. I need to find out, don't I?

Well, technically the builder should have really used noggins as 2.5 metres is 8feet ~ and thats the requirement for spans over that size....

Building regs state

"On joist spans over 2.5m, strutting is required to prevent joists twisting when loaded. For spans of between 2.5 and 4.5 m only one row of strutting is needed, at the mid span position. For spans over 4.5 m two rows of strutting will be required, positioned at the one third and two third span positions.

Solid strutting should be at least 38 mm thick timber extending to at least three quarters the depth of the joist. For example, 200 x 50mm joists would need at least 150 x 38mm timber used as strutting.

Herringbone strutting should be at least 38 x 38mm timber but can only be used where the spacing between the joists is less than three times the depth of the joist. Hence for a 150 x 50 joist, herring bone strutting can only be used up to a spacing of 450mm but for a 200 x 50 joist, a spacing of up to 600mm would be satisfactory."

It might be worth pulling the floor up, getting noggins fitted down the midpoint of the joists (offset from each other to enable fastening the next one). Make sure they use screws...not a nail gun)

And it would also be useful if you detailed how the floorbards are fastened down?
are they nailed??

if so....that will be a big part of the problem. Get them all screwed down ...even though it is way more time consuming, nails (even with punched and buried heads) work loose over time and squeaks emerge...

 

[Manks]

and1c

The boards are screwed down as far as I am aware.

Manks

 

[and1c]

and1c

The boards are screwed down as far as I am aware.

Manks

Just how aware are you though

being serious, if they are not screwed down, then screw them down!

Otherwise you could always do the old 'talcum powder along the floorboard gaps trick' (sprinkle it and brush it in to all of the seams) which will prevent a lot of the creaking, but for how long is anyones guess and its not a satisfactory long term remedy IMO.

As per my previous post. Noggins at joist centres and firmly screwed floor boards should sort it.
if you dont want to pull the floor up again, ensure floor boards are screwed securely (this can make a massive difference to noise)

 

[Manks]

I am speaking to the builder tomorrow, I will ask him if there are any noggins.

 

[^woody^]

T&G floor boards tight together should be quite squeak free.

If they have shrunk and there are gaps between the boards then consider unfixing them and knocking them all together to tighten them up. But wait a few weeks for them to dry if newly laid, as they may shrink more

A 'no-noggin' issue would be more prone to squeaking near the centre of the floor, but if the boards creak around the edges of the floor, then it more likely to do with he boards and the fixing.

Another thing to check is if the joists are secure in the wall or on hangers. If they are built in, and there are gaps around the joists, then they may be flexing slightly at the ends.

 

[Manks]

It does squeak towards the middle of the floor.