Screw Sizes / Lengths

[Skavenger]

Hi;

For fixing roofing battens to gold cladding on to the side of a timber framed workshop what size screws should I use.

The battens are 38 x 50 (D x W) and the timber that they will be screwing into is 3 x 2 (70 x 45).
According to the info I have been looking at the screw length should be no more that 2/3 the combined depth of both pieces.
So 38 + 70 = 108 / 3 = 72mm

So a 70mm screw length?

As for diameter 4 / 4.5 or 5mm?

Thanks

 

[big-all]

70mm/3" and 4or 4.5mm/no8 or 10s will be fine

 

[Diver Fred]

I was taught the 'Rule of Thumb' when fixing timber the that the screw should be 2/3's in fixing, 1/3 in what is to be fixed.
However in your case 3" is an absolute minimum.

 

[big-all]

I was taught the 'Rule of Thumb' when fixing timber the that the screw should be 2/3's in fixing, 1/3 in what is to be fixed.
However in your case 3" is an absolute minimum.

must admit i had assumed 19mm tile baton assuming 38x50 was a typo and actually 19x50mm or 19x38mm tile baton
but suppose i could have asked