I have a 5x8M freestanding shelter at the back of my property that leaks. I want to repair this and have a decking area underneath. I had a contractor lined up to do the shelter but he has let me down so I'll be doing the work now. excuse my lack of knowledge/correct terms.
The original shelter is constructed of 6 square steel frames joined together with 3x2" rafters covered with perspex as a flat roof (see pics, part dismantled). It is a terrible design and has leaked for several years with many of the timbers rotting.
My plan was to dismantle it, cut the steel supports shorter (as too high) and create a fall to the fence side. Will the replace the timbers and cover with transulcent GRP box profile.
However while dismantling it I have become concerned about the stability and strength of the structure. Looking online most comparable structure designs would use much larger timbers. Having said that I don't know how the steel compares to these all timber designs.
My questions are:
1 - can I get away with my proposed design with slightly larger rafters e.g. 4x2 or 5x2?
2 - can I put in some strategic timber or steel supports to make the structure more rigid.
3 - If I should consider redesigning structure entirely how would I best do it, really need to keep existing posts as decking area already underneath.
4 - Any advice on details like fixings. I've got a load of decking screws so was wondering about using them with metal and rubber washers for roof panels.
Any advice appreciated.
