You ll want to use both longer sheathing nails and longer roofing.
Roofing over skip sheathing.
Open sheathing also called skip sheathing is composed of boards spaced apart.
When a cedar shake roof needs replacing the shakes should be removed and the skip sheathing sheeted over with solid plywood.
Osb or 1 2 plywood over skip sheathing makes for a much stiffer roof deck resists problems with expansion better and obviously doesn t require all the hassle of removing it.
Skip sheathing for cedar shingle shake roofs used to be very common in this area of the country and we never remove it or seen anybody else remove it for that matter.
This provides added protection against ice dams.
Most cedar shake roofs were installed over skip sheathing a poor substrate for asphalt composition shingles.
Over spaced board roofs number p300c january 2006 when replacing roofing it is often necessary to cover spaced boards with a solid roof deck.
However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life.
By code you cannot have three layers on a roof.
Was your roof originally built with shiplap.
Over roof insulation the gable overhang has been cut flush with the wall sheathing.
Wood shingle and shake roofing is best applied over open sheathing because the spacing between the open sheathing allows.
As more and more layers of the roofing kept being added there was a minimal chance that any water was going to be able to work its way through your roofing deck.
Until the 1940s exterior grade plywood was not available.
If you re replacing your cedar shakes roof check out our discussion of re sheeting over skip sheathing.
Roof decks on homes built before 1970 are often 1 8 fir pre plywood shiplap.
Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing.
This type of roof sheathing is used under wood shingles and shakes which usually require ventilation on both sides of the roofing material.
After you strip the roof do spot repairs to the existing sheathing where needed then go right over it.
When the panels are attached over the.
Apa rated sheathing panels which include plywood and oriented strand board may be used for this purpose.