hi all
this is my first post and i hope in the right forum..
I'm planning to build a 7.200mts x 3.900mts polycarbonate roof over my decking using wickes 900x4mts sheets..i have a plan how i'm going to build it but not sure if it be strong enough to hold up the weight of the snow..
here is what i planned...
6x2 ledger against my extension wall under the soffit boards at 7.200mts long fixed back with 12mm studs and resin as the wall is lightweight soft blocks, celcons i think...fixings at 700mm apart
6x2 header beam bolted to 4no 4x4 posts set in concrete with a span of 2mts apart with around 600mm cantilever on each end posts and braced with 4x2 from the post in a angle..
6x2 joists spanning at 3.900mts between ledger and header beam fitted on joist hangers..the spacing between rafters will be 900 mm centers for the sheets with 4x2 noggings halfway.
The Polycarbonate glazing bars fitted on top of rafters with the sheets in between them.
There is not a lot of fall on the roof due to the height of the soffits so it be about 200 mm lower at the header beam.
I believe the snow load is 0.6kn/m2 so for that size roof it would need to handle nearly 2 ton if i'm correct?.
That to me seems a lot of weight of snow let alone the weight of the timber work itself and i'm worried it might be to heavy on the joist span or even on the ledger as the wall is soft blocks
I can't find anything on the internet giving calculations on the timber framework to take that weight so i hope someone could tell me my design will be acceptable.
Many thanks
this is my first post and i hope in the right forum..
I'm planning to build a 7.200mts x 3.900mts polycarbonate roof over my decking using wickes 900x4mts sheets..i have a plan how i'm going to build it but not sure if it be strong enough to hold up the weight of the snow..
here is what i planned...
6x2 ledger against my extension wall under the soffit boards at 7.200mts long fixed back with 12mm studs and resin as the wall is lightweight soft blocks, celcons i think...fixings at 700mm apart
6x2 header beam bolted to 4no 4x4 posts set in concrete with a span of 2mts apart with around 600mm cantilever on each end posts and braced with 4x2 from the post in a angle..
6x2 joists spanning at 3.900mts between ledger and header beam fitted on joist hangers..the spacing between rafters will be 900 mm centers for the sheets with 4x2 noggings halfway.
The Polycarbonate glazing bars fitted on top of rafters with the sheets in between them.
There is not a lot of fall on the roof due to the height of the soffits so it be about 200 mm lower at the header beam.
I believe the snow load is 0.6kn/m2 so for that size roof it would need to handle nearly 2 ton if i'm correct?.
That to me seems a lot of weight of snow let alone the weight of the timber work itself and i'm worried it might be to heavy on the joist span or even on the ledger as the wall is soft blocks
I can't find anything on the internet giving calculations on the timber framework to take that weight so i hope someone could tell me my design will be acceptable.
Many thanks
