Should 3/8 plywood sheathing installed over 1x6 wood planks be nailed to rafters or nailed to the planks? And is there a code for either way?
Thank you in advance!
Image?
Plywood can be fastened atop planks.
Nailed to the rafters, with code mandated gaps between panels, and 1" longer nails than usual to account for the 1x6 sheathing thickness. Shims may be needed if there are gaps between the 1x6. Post photos.
I agree with the above comments and also include that the nailing schedule (or approved fasteners) is typically a 6" (along seams) and 12" (in the field)
…that is unless you are in a high wind area, then more nailing may be needed.
I agree with the previous sheath over plank comments, also.
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I am trying to find code related answer and can’t.
This goes beyond SoP. You would require destructive analyses.
One would have to determine if planking was properly secured with correct fasteners and schedule.
Likely the 3/8" inch sheathing was added to straighten out the roof deck due to cupping warping planks.
Moreover; when planked properly, why would an extra layer of 3/4" inch sheathing be required to be fastened in the same fashion as if the were no planks when the planks are properly secured?
Anyone have code on this procedure?
Are the 1x6 skipped sheathed?
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3/8 sheathing. Shingle manufacturer required it because the planks had up to 1/2" spacing. The planks started out in good condition but because the nailing was done directly on them, some have split and some have chunks knocked out.
The home 1950’s or earlier?
Maria, that is not skipped sheathing. Typically, 1"×4" inch or 1"×6": inch boards of lumber is installed with a 3.5″ (maximum) space between each board.
Be ir the first layer of sheathing is boards/planked, it is not Skipped Sheathing.
Skipped Sheathing is used when wood shakes/shingles, tiles, or metal roofing is the roof covering.
Mr. Cyr would be able to shed more light on the subject.
I would report fastener shanks protrusions too long.
I can not make out the insulation under the insulated pipe. Is that vermiculite?
Maria, you have anymore images of the attic space?
Built in 1967. I didn’t refer to it as “skip sheathing”. They are 1x6 boards that have up to 1/2" spaces between them. The shingle manufacturer required 3/8" plywood be installed over to assure every shingle would grab wood when nailed. My question is should the plywood been nailed to the rafters or directly to the boards?
My mistake. I beg your pardon.
My question is should the plywood been nailed to the rafters or directly to the boards?
Depends what you observe. If boards/planks are insufficiently fastened I would fasten to both.
Wait for others to reply. I am still looking for compliance.
To the rafters would be the best. I don’t think you are going to find a code reference for this exact scenario (plywood installed over planking), but in general, all sheathing should be fastened to the rafters.
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Agreed. Where are you located Maria?
Metairie, Louisiana - Hurricane area
Exactly what I thought, plus eliminates those long nails in the attic that are a serious hazard. Doesn’t make sense there isn’t a code somewhere.
In florida, they are required to be nailed every 6" with 8D nails into the rafters/trusses. Those nails arent going to do much if they are only nailed into the planks. Screws would have been much better.
But again, you cant know if they nailed into every truss or not during your inspection.
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Yeah, those old boards dry up and shrink a lot. Aside from the nail catching thing I was told by a good roofer once that he won’t install over all those boards because all the gaps can catch the felt/underlayment and tear it as things expand and contract. I once helped a buddy do a roof on his 1960s house with 1X6 underlayment and talked him into covering with thin plywood. The gaps and general condition of any roof deck that is 60+ years old is poor enough that there should be something better in place for new shingles. This is a perfect example of where the lowest bid screws the homeowner. Spending $1000 doing it right can result in the job lasting 25 years instead of 10 (or less). One last rant… Anytime I have friends/family getting a roof bid I tell them any roofer that doesn’t look in the attic should be immediately crossed off their list. I couldn’t imagine installing 20K worth of roof and not even looking at what I’m attaching it to.
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Is there a Florida code for that requirement?