Long thin screws to secure insulation + tilebacker board to brick with wall plugs?

[JP_]

I have some washers to help hold insulation boards in place, but the 6mm x 120mm screws (Wickes multi purpose) I bought are too bit - they go in but the screw head is too large.

I think I need something like a 5mm 120mm screw, but not finding many options. Can anybody recommend one?

Although, maybe a better option is to get something bigger, like these Load Spreading 60mm Polypropylene washers - I assume the screw head will sink a little into the insulation.

It is for 50mm Kingspan + 10mm STS tile backer board, (plus about 10mm gap/adhesive foam) to go into brick. Then it will be tiled, so obviously needs to be pretty flat, maybe flatter than if rendering (eg on external insulation)

I am wondering if I can just use a 4.8 x 120mm drywall screw - but will these securely fit in a wall plug?

These don't work:

 

[^woody^]

You only need literally a couple of screws to hold the insulation before you fit the board. And those screws dont need washers.

If you feel the need you can cut plastic from a food carton or suchlike, or if you have steel banding use that.

 

[JP_]

Ended up getting these, nice and solid.

 

[Deleted member 292770]

And those screws dont need washers.

the boards do.

 

[phatboy]

Could you get away with these? https://www.ironmongerydirect.co.uk....8-x-100mm-black-phosphate-pack-of-500-823070

 

[JP_]

Drywall screws would / should be ok, but they need to be at least 12cm. The ones i found seem perfect for the job.

 

[Deleted member 292770]

Ended up getting these, nice and solid.

View attachment 258351

View attachment 258352

just fyi you need more screws.
16” spacings max for wedi board.

 

[Diver Fred]

Are you tiling a bathroom? If so then you should be using Stainless Screws; length long enough to be in the wall structure a minimum of 60mm (if the plaster is still on the wall then it's 60mm into the brick).
The metal disks are much better to use than plastic ones. The screw head will be 'lost' in the tile adhesive.
I reckon on 20 screws per board spaced evenly.

 

[Deleted member 292770]

Are you tiling a bathroom? If so then you should be using Stainless Screws; length long enough to be in the wall structure a minimum of 60mm (if the plaster is still on the wall then it's 60mm into the brick).
The metal disks are much better to use than plastic ones. The screw head will be 'lost' in the tile adhesive.
I reckon on 20 screws per board spaced evenly.

why stainless?