[skloon]

The 12 year old roof on my garage is kaput, mostly sun damage on the west exposure and I discovered that their was no first course laid and as a result the first few inches of the OSB are like bad cheese. Can I cut up 16" or so from the edge and just replace this piece or do I have to pull off the full sheets and replace ?

 

[Ed the Roofer]

I feel that anything less than 24 inches wide leads to problems with dimensional stability, so go at least 2 feet up with the wood decking replacement.

Ed

 

[VaViaCo]

H-clips

whether you take off 16" or 24", use H-clips between your new wood and what remains of the old and sag won't be an issue.