screws for cement board

[jonnyc]

got quite a big floorwhich needs overlaying with xl cement board(trinmline) similar to hardibacker.
just found the screws delivered too long for heat pipes below.
whats the best type of screw for these boards .

screwfix is open and my best bet today.
any suggestions

 

[area tiling]

Turbo golds I find work well , spax!!

 

[Rookery]

When I fix 6mm Hardie I use 25mm MDF Tite screws from Screwfix.

 

[AliGage]

Turbo golds everytime.

 

[Qwerty]

Turbo golds here too!

 

[Mr Tiler]

Drywall screws here come in all sizes

 

[cam_low]

turbo gold zinc screws non rust, plasterboard screws rust tea bag.

 

[charlie1]

Turbo gold 4 x 25 mm

 

[Spud]

Drywall screws here come in all sizes

Ash never use dry wall screws for screwing down hardie or plywood they arent strong enough and the threads on the screws are narrower than wood screws so dont grip into the substrate the same way a wood screw will do

 

[AliGage]

There is a clue in the name!

 

[White Room]

Drywall screws here come in all sizes

The smaller thread are for dry lining metal systems and the course thread for timber but would use neither for fixing to the floor...

 

[Stef]

Turbo golds!!!!

 

[widler]

If drywall screws can hold a 12.5/15/mm 8x4 plasterboard upside down on a ceiling into wood for decades it will hold a floor down.

 

[widler]

Oh and you screw a floor down with twice ss many screws as well.
Wheres the logic lads in not using dry wall screws ?

 

[White Room]

Oh and you screw a floor down with twice ss many screws as well.
Wheres the logic lads in not using dry wall screws ?

Why use dry wall screws when theres other screws that are more appropriate for the job....

 

[radim]

plasterboard screws here....
plenty of strips lying on site, just need to pick them up...

 

[Stef]

Try screwing plasterboard screws into Hardi with an impact driver & you will find out why they are not suitable!!!!

 

[Spud]

If drywall screws can hold a 12.5/15/mm 8x4 plasterboard upside down on a ceiling into wood for decades it will hold a floor down. 

The plasterboard gives when shear stress is applied where plywood and hardie don't ,under stress drywall screws snap very easily but if you wish to use them then go for it

 

[nakhodka2002]

What size of turbo gold or spax would you use for hardie? I found that 3.5 mm x 25mm a too weak and don't pull board strong enough to the plywood, where is original hardie screws pull very tight

 

[Qwerty]

I have sheared the heads off of drywall screws before, never with turbo golds though

 

[mike1979]

I use spax 25 mm but we aren't going to have a row over screws are we

 

[Spud]

I stopped a builder using dry wall screws once and asked him to screw down a floor with wood screws, I didn't specify which ones and went off for breakfast came back and found him putting in shanked wood screws he didn't take it that well when I asked him to change them for fully threaded screws doh !!!

 

[White Room]

I use spax 25 mm but we aren't going to have a row over screws are we

There good screws, I use them for the marmox washers....

 

[On one]

What size of turbo gold or spax would you use for hardie? I found that 3.5 mm x 25mm a too weak and don't pull board strong enough to the plywood, where is original hardie screws pull very tight

Maybe your driver/bit could be the problem. Recently I changed over to use an impact driver,but forgot it one day and asked to use a joiners 18v DeWalt cordless......with the right driver and the right bit it would pull the screws all the way thru the Hardie

 

[SJPurdy]

Hardie minimum screw specification for fixing to wood floors is:

No. 8 shank (4mm, I think) corrosion resistant screw with 9.5mm diameter counter sunk head. Length to penetrate substrate by 19mm ( or thickness of substrate if less).