New Decking for old roof

Old 02-03-04, 05:39 PM
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New Decking for old roof

I Have to put new shingles on my house this summer and I would like to replace my old Decking(Currently 1X6 Boards) with Plywood.(House Was Built in 1944)
Is it possible that I remove only the shingles and put the plywood directly over the old decking.
Old 02-04-04, 05:33 AM
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Why do you want to replace the 1X6 decking? Is it warped?
You can add plywood over the old roof decking if you want, but you'll be adding a lot of weight.
You will likely have to reinforce the rafters with support.
Old 02-04-04, 05:56 AM
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Spaced decking is typically 1" boards spaced about 2" apart. Spaced decking is a method used on old houses when the roofing material is cedar. If we want to install shingles, we have to install plywood over the decking. This is common and no problem, as long as our fasteners go into the rafters.

I must ask the same question. Why do you want to remove the 1" boards? I personally prefer those old 1" boards to the plywood.
Old 02-04-04, 04:01 PM
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Some shingle manufacturers require you to resheet(go over the exhisting decking) a roof deck that is 1x material if the exhisting boards are not up to nearly perfect standards.
I have resheeted many roofing projects, and weight was really never much of a factor. Make sure that you use a larger Drip edge to cover the extra thickness at the edges. I also don't have a problem shingling directly over the 1x as long as they are in good shape and you renail all the old boards into the rafters.
Old 02-04-04, 04:19 PM
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Yes kwik I forgot to mention the drip edge. This is not a must but highly recommended... otherwise you will see the plywood edge quite easily and possible water damage may occur.
Old 02-07-04, 04:30 AM
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The major concern when roofing over plank decks is the cracks between the boards. You may have to adjust your shingle exposure every now and again so that NO shingle nails end up in the cracks. If the planking is diagonal, this is impossible to do and you should definately sheet with plywood. Also, Ice & Water Shield may not seal around the shaft of the nail if is in the crack. Ice & Water Shield needs some compression to get a good seal.

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