Plastic roof lean to. Timber advice would be appreciated

[FiremanT]

I am building a lean to behind a reasonably large shed. It will be out of sight so prettiness is not the main consideration. I am able to do the work, but am a little concerned about the design of the timber.

Some images on t'net suggest sing 6" x 3" for the joists. This seem s a bit excessive, as the only load is the plastic sheeting plus snow. The roof will be 3M x 4m, the pitch being formed by one side at 1.8M and the other 2.4M.

I suppose the main thing is knowing how big I HAVE to go for

a) The vertical supports (and their spacing)
b) Joistsn (presumably I would space these the same as the joists?)
c) Purlins (I understand these should be 600mm centred.

Are there any "standard" plans around?

Any advice would be appreciated.

Thanks

 

[pinenot]

You haven't actually said what the lean-to is intended for, nor what size etc.
Assuming it's a shed like structure for the base and top runners and the studs 2"x2"will be fine and 3"x1" or there about for the lean-to roof to carry plastic, however if it's corrugated the plasic will nedd little in the way of support other than a mid span cross bearer.
Here's a whole load of plans, just adjust to suit your requirements - http://www.shedplansz.com/lean-to-shed-plans

Good luck...pinenot

 

[FiremanT]

You haven't actually said what the lean-to is intended for, nor what size etc.
Assuming it's a shed like structure for the base and top runners and the studs 2"x2"will be fine and 3"x1" or there about for the lean-to roof to carry plastic, however if it's corrugated the plasic will nedd little in the way of support other than a mid span cross bearer.
Here's a whole load of plans, just adjust to suit your requirements - http://www.shedplansz.com/lean-to-shed-plans

Good luck...pinenot

Great. Thanks for that, I shall have a good like this pm. Meanwhile, you are right, I wasn't very clear. The lean to will be about 4M x 3M, On side 1.8M the other 2.2M or thereabouts.

It will be used for general storage, and, in the warmer months, space for working on a bench