[edessex]

I've got an old shed, about 8ft wide by 16ft long, standard apex roof.  The shed is in very poor condition; the roof needs replacing and the whole thing is leaning.

I am planning to remove the old roof, and replace it with a single sloping roof (for ease).  Because the shed is leaning, and considering its current state, my plan is to set some wooden posts in next to the shed walls, and use them to pull the shed straight, and hold it upright.  The roof can then be fitted on these posts, so there would be no excess weight carried by the shed walls.

I was thinking of 6 posts, one on each corner and one halfway down each side, would that be enough, or would I be better with 8?

Are 4"x4" posts ok, can I go thinner (cheaper)?  I am planning to use corrugated / box sheeting for the roof.

Is there a suggested pitch for a single sloping roof?

[spandit]

Are you going to make more work for yourself when buying a new shed is an option? To get the resistance to the lateral force you're going to need to sink the poles in pretty deep and they'd need to be substantial, might even go bigger than 4x4...

[edessex]

In this case repair is the only viable option; I would need planning permission to replace.

[MAK]

I would cross brace across each corner - less wood needed too. If you wanted to make a stong job then brace at the very top and bottom and try and pick up any vertical struts within the shed.If you ensure that the new roof holds in each side then you will achieve a stronger unit. Maybe puts some noggins onto the shed sides ( internatl or external and then fix the roof to these. Any wire? Drill thru at top of each side and block outside to hold wire - tighten wire at opposite side with a simular block arrangement. keep it cheap 

[Bodger]

Unless I've missed it, you haven't actually said what sort of roof you're putting on it. Without knowing, I'd still go for something sturdier.

[edessex]

Sorry, not been on in a while!

I'm planning to fit a corrugated roof, either metal or onduline, straight onto framework; no boarding underneath.

[LoveDevon]

Hi
 if i were you i would go 6x6 tanilised timber post concrete in at least 600mm . 6 post would be enough as that would only give you a 8ft span.

[philcaegrug]

If you are using onduline you'll have to put the rafters quite close together or it will sag in between and if possible put in some diagonal bracing in the walls as this should hold it more square.

[chrismahon]

Our shed was leaning over and it only needed one diagonal brace to set the whole thing square again. Not keen on Onduline because it needs so much support underneath. I still use wood and felt.