Which screws to fix a creaking floor?

Oh for heaven's sake!

 

Strangely, I know that too. But think about what that unthreaded part and the smooth underside of the countersink does when met with wood. It squeaks when the wood flexes.
Full-threaded screws don't squeak. The threads don't allow one to move against the other.

 

For laminate floor I have used Quickstep, 7mm with 4 edge champher and their own 3mm dense underlay.
Superb finish and dead solid.
No glue needed...and resistant to high heels !
I suspect that full thread or part thread on screws will do the job as the timber humidity has stabilised and wont vary much now.(not a carpener tho)
Might be a different story on new build and wet timbers....particulary low grade OSB board...which im my opinion is S******....and should only be used for shelving.
Look for where boards have been lifted before..as you may want to add extra support...and gain easy access for camera/boroscope as mentioned before.
RS

 

Jesus Christ, looks like Swiss cheese! It won't be the tongue and groove causing the squeak, the timbers rubbing against a fixing somewhere causing it. When screwing boards down, I stand on top of the board to hold it as tight against the joist as possible, then screw it down. Sometimes if a joist is a bit high, the adjacent joists will have a small gap between it and the floorboards, putting weight on it whilst driving screws will narrow the gap as tight as possible. Find a squeak, remove the screws from the joist and its adjacent ones, and screw it back down whilst standing on top of the joist you're screwing into.

The squeak by the stud wall is unfortunately caused by the nails that are fixed into the sole plate through into the flooring below rubbing with the flex in the floor. Unless you want to pull your skirting off, remove some plasterboard and lever the nails out with a claw bar and refix with screws, you're probably going to have to live with it I'm afraid. Or you could try removing your skirting and tapping in some thin packers under your wall near the nail positions, then pumping clear silicone along the wall floor intersection. It's a bit of a bodge, but if it works, it works.

 

Yeah leave the packers in, it'll hopefully stop any flex which will hopefully stop any squeak. If it's a possibility to take the nails out of floorboards and replace with screws then go for it, but if the boards are going to get ruined try to drive a screw close to the original nails to try to pull the board down tight. I know its a bit late as you've basically done it already but watch out for cables and pipes yeah?

 

Yeah the same screws will be fine mate.

 

You should try the lottery op as if I was to screw that many screws down I’d hit every pipe possible lol

 

He clearly doesn't need to win the lottery if he can afford that many screws!