replace garage roof

[ih]

hi i intend to replace my old asbestos garage roof with new flat roof. My knowledge on roofing is poor. Need help advise on the spec that i can follow. the size is approx 6x3 metre.thanking in advance.

 

[garyrayne123]

Does it need to be flat? Pitched roof is best.


use 225mm x 50mm c16 treated timber solid joists at 600mm centres for 3m span. solid blocking will be required at mid span or herring bone strutting.

 

[ih]

thanks for the reply appreciate your advise on pitched roof but due to budget and adjoining garage flat roof is necessary.

 

[Deluks]

If like mine, the asbestos sheets are fixed to sloping steel rafters, then simply over board these with ply/OSB, and felt with a good quality product.

 

[noseall]

use 225mm x 50mm c16 treated timber solid joists at 600mm centres for 3m span.

erm, my calculator says 150mm x 50mm for a 3m span. maybe at 400c/c but still better than 225mm x 50mm.

225mm will deal with up to 4.8m. at the right centres.

 

[garyrayne123]

both solutions work!

 

[noseall]

both solutions work!

aye -

-but timber 'aint cheap.

 

[garyrayne123]

lol sorry i do the drawings at work and sometimes get told off the buyers when i over specify. the thing is if out doesnt work i get the blame, so i let them decide what to cut back on.