Screwing down chipboard flooring

[jrb43]

Yep, one day you're doing wheelies on your BMX, the next you're....

In the latter stages of the one of the most overthought projects ever:

I'm going to use EBT+ adhesive between joist and 21mm chipboard, PVA between T+G and then screw the boards down. All ok so far?

Plan is to use TurboGold PZ Double-Countersunk Multipurpose Screws 5mm x 60mm (single threaded). Now:

Do we agree with my choice of fastener?
How many per board?
In a line or staggered across the width of the joist?
No hole, just drive the screw through with the impact driver?
Pilot hole in the board?
Clearance hole in the board?

Obviously if there's a squeak, I'll be required to leave the family and disappear into the woods so reasonably high stakes on getting it right ...

[kiethton]

That's perfect, go for 60cm gaps on the screws if you want to over-do it

[Stegel]

jrb43 said:

Yep, one day you're doing wheelies on your BMX, the next you're....

In the latter stages of the one of the most overthought projects ever:

I'm going to use EBT+ adhesive between joist and 21mm chipboard, PVA between T+G and then screw the boards down. All ok so far?

Plan is to use TurboGold PZ Double-Countersunk Multipurpose Screws 5mm x 60mm (single threaded). Now:

Do we agree with my choice of fastener?
How many per board?
In a line or staggered across the width of the joist?
No hole, just drive the screw through with the impact driver?
Pilot hole in the board?
Clearance hole in the board?

Obviously if there's a squeak, I'll be required to leave the family and disappear into the woods so reasonably high stakes on getting it right ...

I would recommend these, at 150mm centres on edges, 200mm centres elsewhere. They pull the board down tight to the joists - not a peep! The screws you suggest are ok, but there is a risk of “jacking” between the board and joist.

https://www.screwfix.com/p/spax-tx-countersunk-sel...

[bennno]

Any pipes to avoid, 60mm might be more than required.

[Simpo Two]

jrb43 said:

No hole, just drive the screw through with the impact driver?
Pilot hole in the board?
Clearance hole in the board?

I would put a clearance hole in the board; that way the screw can pull the two parts together as intended. Depending on the relative grip and softness of the two materials you may not need countersinks.

People these days often use impact drivers and tend to keep the power on 'dakka-dakka-dakka-dakka-dakka-dakka-dakka-dakka-dakka-dakka' until the screw is halfway through the board. Just stop when the head is flush. If you're using a civilised device - ie something with a torque settting - then you can set that until it's just sufficient.

50mm screws would be fine.

[Turtle Shed]

Can I ask why you would glue all of this down? Won't screws on their own be enough, and then you can take it up again should you ever need to.

I know that glue will make even stronger, and stop any possibility of creaking/movement.

[KTMsm]

If you use the spax above no need for a clearance hole

If you use the screws you wanted then I would drill one

The D4 glue is excellent, if using PVA I'd squirt then brush it all over the jointing face - which you will soon find is time consuming

Essentially the proper tools for the job have been invented to save you time. However, if you have plenty of time and less money, do it your way

[Little Lofty]

Turtle Shed said:

Can I ask why you would glue all of this down? Won't screws on their own be enough, and then you can take it up again should you ever need to.

I know that glue will make even stronger, and stop any possibility of creaking/movement.

If using D4 glue (its all anyone should use these days) you don’t need loads of other fixings. The glue system is stronger and quieter the screwing alone. You get squeaks from the joints rubbing together and around the fixings, pva type glue does not prevent this 100%, if you use D4 it doesn’t squeak.

Edited by Little Lofty on Saturday 1st March 16:49

[ThingsBehindTheSun]

jrb43 said:

Obviously if there's a squeak, I'll be required to leave the family and disappear into the woods so reasonably high stakes on getting it right ...

Ah, this reminds me of my 80s BTL house where I put hundreds of flooring screws into the chipboard to stop the squeaks (they drive me mental). All it seemed to do was move the squeak somewhere else despite how many screws I used.

I finally thought it was squeak free and I had the carpets laid. As I was walking around admiring how good it looked I heard a squeak......

[LooneyTunes]

Stegel said:

I would recommend these, at 150mm centres on edges, 200mm centres elsewhere. They pull the board down tight to the joists - not a peep! The screws you suggest are ok, but there is a risk of “jacking” between the board and joist.

https://www.screwfix.com/p/spax-tx-countersunk-sel...

We've used those before with good results. Trying these for loft above my garage as they're a fair bit cheaper on a per screw basis: https://www.screwfix.com/p/optimaxx-tx-countersunk...

[wolfracesonic]

Little Lofty said:

If using D4 glue (its all anyone should use these days) you don’t need loads of other fixings. The glue system is stronger and quieter the screwing alone. You get squeaks from the joints rubbing together and around the fixings, pva type glue does not prevent this 100%, if you use D4 it doesn’t squeak.

Edited by Little Lofty on Saturday 1st March 16:49

Also wear gloves and your crappiest pair of trousers, the stuff tends to get everywhere. Google joist and joint adhesive, you can use it for along the top of the joists and the board joints, just like it says on the tin, saves faffing with two separate products. Caber and Egger make stuff.

[jrb43]

Thank you so much everyone: some great bespoke product recommendations there that I had no idea about.

Hopefully cue the VW Golf ad with the squeaky earring 😊