Subfloor Nail / Screw

[HadAGo]

I’ve started doing a few jobs around the house, one being a ‘bounce’ under the lino in the bathroom, I’ve just pulled a section up as I’m looking to replace it at a later date anyway so will just seam together again for now, it seems that it’s missing a screw / nail plus one has gone in at an angle which I’m wondering if it will require removing.

No signs of any other issues or moisture it’s just missing a screw / nail and it’s the heaviest trafficked section as its where you enter / exit the bath.

Does anyone know which screw / nail I need, I though they were general nails but looking at the one at an angle it has a thread.. Nail gun?

I’ve attached a few images, unable to capture the section that needs fixing down so just tried to show the bigger picture

Cheers!

 

[KenGMac]

HadAGo, good evening.

From the images posted, it appears that there is a ply layer on top of what looks like Chip board, having said that images difficult to be sure.

Standard practice to lay ply on to any flooring, especially T&G wood, but what should happen is that the ply is screwed down at 100.mm. C/C in all directions, [that is the boring bit of fitting ply under floor] this to give a solid flat base for the final finish.

Suggest you consider using screws to firmly fix the ply, as for length of screw ?
Chip Board will [probably] be 18.mm
Ply ??? possibly 5 or 6. mm??? cannot see it

Choose a screw length so that is does NOT protrude too far below the under side of the Chip Board, pipes and cables lurk everywhere???

Set the screws at 100.mm C/C

Ken

 

[HadAGo]

Hello Ken,

Thank you for your reply, the last photo was an attempt to show the thickness of the ply but your correct it’s 5-6 mm, it’s hard to see what’s underneath so would like to keep the screws as short as possible in case I hit something underneath.

I can not remove one that is already in place as there are no screw heads, hence why I thought they were nails at first.

Can you recommend a screw I could try?

Sorry for the question but when you say set the screws at 100mm C/C I don’t follow (quite new to DIY). But I’m trying!

 

[Deleted member 174758]

Sorry for the question but when you say set the screws at 100mm C/C I don’t follow (quite new to DIY). But I’m trying!

100mm on centre, or 100mm apart in both directions laid out in a in a regular grid.

At one time we used to use flat headed tacks for the task, although screws became de rigeur maybe 20 or 25 years ago when collated screw guns and collated flooring screws became available (faster and much less hard work).

With 18mm chip and 5mm ply when hand screwing your screws should be something like 4.0 x 20 to 25mm and the style like Spax or Reisser screws where the heads cut their own recesses as they drive in are to be preferred because you really need to flush or slightly recess the screw heads in order that they don't end up telegraphing through the finish flooring. 5.0mm screws won't flush readily, whilst screws smaller than 4.0mm don't have big enough heads to hold the plywood and are more prone to popping IMHO

 

[HadAGo]

Brilliant thank you for the info, I’ve had a look around for what you recommended and found these:

https://www.amazon.co.uk/Reisser-Cutter-8200S220400204-Yellow-Woodscrew/dp/B001W2CHHO

I’ve bought a Wall/Floor scanner to check for pipes etc and will be screwing by hand for more control, only need two possibly three where they missed when fitting.

Thanks for the replies.