The greenhouse build finally continues! Its only taken me two years...
Back wall will be a wooden frame, with osb- then insulation and wooden cladding on the outside.
the front wall (south facing) will be reused double glazed window units, with the west wall (up against the fence) a solid one, and the east wall mostly door! Roof to be polycarbonate 16mm triple wall, resting on a timber frame. Which is where I have some building-questions...
How do you find out what thickness of timber to make the roof from? There are span tables, but I can’t seem to work them out! They seem to assume heavy roof tiles (as are standard here), not light polycarbonate sheets. I want to use as little timber as possible so I don’t block light, but I also don’t want the roof to collapse!
A beautiful picture- with some labeling to ensure I have terminology right:
I'd like to use a 6x2 piece of timber for the ridge beam, and 4x2 for the rafters- putting the rafters 1.2m apart. But I've no idea if this is safe! Other than putting it together and seeing how creaky it feels, any advice?
The roof projections are 1.8m (28 degrees) for the south facing saide, 0.8m (and 34 degrees) for the north facing side- so it isn’t a huge roof. The greenhouse itself is 2m wide, 4.8m long. I am in the UK- it rarely snows (and then only a few cms), and I’m in a sheltered position (no huge winds or heavy storms).