Inherited a 10 * 8 shed, which the roof was knackered on. 

I have got the structure up and now onto the roof. I am using OSB for the roof and have 2.4 * 1.2m sheet

However when the OSB is lined up to the ridge there is a gap at the eaves.

Even with a 4ft board the extra 2cm would not cover the gap.

How is this gap catered for normally?

 

 

Don't forget that the shed makers can possibly get 10'x5' sheets for a start. 

 

Was the roof osb originally? It's timber slats on my hand me down shed and they run up slope.

 

 

You'll have to graft a strip of OSB on either at the bottom or move the whole sheet down slope (to overhang) and graft on a strip at the top. Wherever, the "graft" will need a full length supporting strip underneath. 

You could move it down and use a ridge cap like this, if the gap is not too big:

The original roof was osb

 

That ridge cap is probably the best solution.