roof construction basics

[climber101]

hi, beginner roof questions to the roofing experts PLEASE! for my extension

i’ll ask these in the order I think I need to be laying things so feel free to correct me please!

1) Sarking boards first – do you use OSB board and what is common thicknesses for roof?

2) roofing felt next - do you staple this on?

3) Counter battens – (the ones that run from top to bottom) my spec says 38x13mm whitewood –

does that size sound reasonable?
what is it getting at by “whitewood”? Am I understanding treated softwood?
Normal Galvanised nails to secure these battens?

4) Tiling battens – my spec says 50x25mm tiling battens – does that sound reasonable and again is it normal galvanised nails and what size

Last question for now which is more for interests sake am I describing a “cold roof” or a “warm roof” construction?

Many thanks in advance

 

[noseall]

Sarking boards first – do you use OSB board and what is common thicknesses for roof?

sarking boards in Coventry? 18mm osb as a minimum requirement possibly?

2) roofing felt next - do you staple this on?

i would say counterbatten next.

3) Counter battens – (the ones that run from top to bottom) my spec says 38x13mm whitewood –

sounds a bit thin to me.

what is it getting at by “whitewood”? Am I understanding treated softwood?

whitewood is softwood.

Normal Galvanised nails to secure these battens?

yup.

4) Tiling battens – my spec says 50x25mm tiling battens – does that sound reasonable and again is it normal galvanised nails and what size

sounds good to me, yes, to galv nails too.

Last question for now which is more for interests sake am I describing a “cold roof” or a “warm roof” construction?

neither unless you describe the insulation and venting spec. if you are insulating at the rafter detail then it can either be warm or cold dependant upon the position of the insulation relative to the rafter, air gap and ventilation.
if you insulate at the joist detail then warm or cold does not apply.

 

[climber101]

many thanks noseall very helpful !