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old roof is 30" oc

7703 Views 7 Replies 3 Participants Last post by  sun ray
I'm replacing the asphalt shingle roof on my 650 sq ft, 86 year old house. The existing sheathing consists of 1x6 boards. I am replacing the really bad ones. But the rafters are 30 inches apart. I am want to put plywood over the top of the existing 1x6's. I am worried that the extra weight from plywood would create a problem for the old house.
Does anyone know what plywood size is best?
Would H clips help with the sheathing's structure?
How do I deal with the problem of the 8ft plywood not aligning with the rafters?
Any other suggestions or hints?

Thank you,
1 - 1 of 8 Posts
Without talking to your local code department first, the 1" x 6" plank boards offer additional rigidity to the structure, even though the rafter spacing is unorthodox and seemingly too wide for current code requirements.

If the remaining 1" x 6" plank boards, after you do the replacement required of defective ones, are not significantly deflected or pose a structural issue, and do not have a 1" to 2" gap in between each board, you should be able to apply the new shingles directly on top of the existing dimensional deck boards, without any concerns.

But check with your code department first, if that is acceptable, which it should be.

1 - 1 of 8 Posts
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