# Roof sheathing



## Jerry Hiatt

Recently had hail damage to my asphalt shingles. The roofer has been tearing the old roof off and has found that the sheathing is dimensional lumber. Mostly 1x6's. He says it all has to be torn off and replaced with plywood. He says it is not up to code and he has no choice. At my expense of course. Any feedback would be appreciated.


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## ICE

That wouldn’t happen here unless the sheathing is rotten.  Sometimes there are large gaps between the boards and a layer of OSB or plywood is placed over the existing sheathing.  Dimensional lumber is allowed as sheathing.

If you are able, a picture would clear things up.


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## cda

Welcome


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## cda

How long have you been in the house??

How old is the house ?

Any gaps between the boards?


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## cda

I guess it is to late for 2 and 3 opinion


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## mtlogcabin

We run into this all the time and we allow sheathing to be installed over the existing 1x skip boards. You are only adding about 1-2 psf of dead load to the roof. check the shingle installation instructions. They probably require solid sheathing to be under their shingles.


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## jar546

There is no argument for this.  Your situation is not a code issue unless the shingle manufacturer installation requirements prohibit this.


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## fatboy

I'll allow a 1/4" gap, max....otherwise, overlay with OSB. Tearing off the skip sheathing is ridiculous.


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## jar546

fatboy said:


> I'll allow a 1/4" gap, max....otherwise, overlay with OSB. Tearing off the skip sheathing is ridiculous.



Yeah, that gap thing he said and I forgot about.  
Where I am originally from we had this issue all the time as many of the homes had plank roof decking with 1x10's, 1x12's, 1x8's etc.


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## fatboy

Back in the day, I would see them down to basically 1X2's...granted it was a real 1X2, which was actually more like 7/8" rather than 3/4", and the real old growth wood.


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## e hilton

From the Certainteed website, for plain 3 tab asphalt shingles ...

THE ROOF DECK* MUST BE AT LEAST: 3⁄8" (9.5 mm) thick 
plywood, or 7⁄16" (11 mm) thick non-veneer, or nominal 1"
(25 mm) thick wood deck.


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## Mark K

The roofer does not understand the code.  You may find it useful to talk  to an engineer to resolve this disagreement with the roofer.  In any case you should not need to tear off the existing sheathing.

The IRC is for new construction.  When you find situations that are different you are allowed to reference the IBC.

Straight or diagonal sheathing are perfectly adequate for vertical loads.  Plywood provides more strength to resist horizontal loads.  Baring some specific requirement you are not required to install plywood when reroofing  The reference provided is not adequate to impose  such a requirement..  

I suspect that if you were to remove the existing sheathing it would impact a number of details around the perimeter that would increase the costs.

If the gaps are a problem for the shingle manufacture you may need to address this issue if you want their warrantee but this should not be a code issue.  I am aware of the code provisions that reference manufacturers recommendation and I believe that there are legal problems with delegating to manufacture the ability to determine what is code.  

The gap between the boards is most likely due to shrinkage of the wood as it dried out.  I expect that you will find many similar roofs that are performing very adequately.  One easy solution that would resolve the issue of the gaps and would provide more diaphragm strength would be to staple 1/4" plywood to the existing sheathing.  If the IBC doesn't have provision for stapling plywood I am sure a civil/structural engineer could make a reasonable recommendation.   Select staples that would not extend beneath the existing sheathing.

You should not need to tear off what appears to be perfectly serviceable straight sheathing. 

I do not recommend 3/8" plywood for roof sheathing installed directly on the roof joists.  It is limited in the ability to resist concentrated loads.  How would they attach the shingles to 3/8" plywood   There is nothing for a roofing nail to develop resistance.

Bottom line the roofer is not interpreting the code correctly and in any case you should not need to tear off perfectly serviceable 1x or 2x sheathing.  To resolve this mater with your roofer it is likely cheaper to involve an engineer than to pay  for the removing of the existing sheathing.


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## mark handler

http://cornellcorporation.com/docs/...ateForAsphaltShingleApplications_07312014.pdf
GAF Asphalt Shingle Applications
Note:  For existing older installations, if spacing is > 1/8” ≤ 1/4”, install a double layer of underlayment.  If the spacing is greater than 1/4” install a layer of 3/8” minimum thickness APA labeled exterior grade plywood or OSB over the wood planking.


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## e hilton

Hey guys ... go back and read the OP again ... nowhere does he mention gaps between the boards.  He hax only posted once, so its not hard to read.  

Sounds like thr roofer is looking is looking to increase the profit on the job.  If i was the HO i wouod tell him to produce something in writing to support the increase in scope.   Manufacturers installation ibstructions, code section, something.  If the work is already done, or started, i would refuse to pay. Let the roofer lien the job, a lien is no good unless it can be validated, and this one would fail without written backup.


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## jar546

I am going to look at this from the roofer's standpoint.  I for one know what it is like to put shingles on a plank roof that has gaps between the board and often, the boards are uneven.  Inevitably nails land in the gaps and either don't hold a thing and/or just blow right through.  Callbacks suck and finding roof leaks suck too.  It was common practice to have a clause in the contract that once the roof was stripped down, depending on what was found, plank roofs that were not already covered with plywood would then need to be covered in order to do a good job and provide a solid warranty.  With plank roofs, in addition to the gaps between boards and ends also have knots which creates another issue.  
On another end, I always tell people that if the roofer giving you a bid did not look in the attic, don't bother hiring them.


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## mtlogcabin

2012 IRC
R907.1 General.
Materials and methods of application used for re-covering or replacing an existing roof covering shall comply with the requirements of Chapter 9.

R905.1 Roof covering application.
Roof coverings shall be applied in accordance with the applicable provisions of this section and the manufacturer’s installation instructions. Unless otherwise specified in this section, roof coverings shall be installed to resist the component and cladding loads specified in Table R301.2(2), adjusted for height and exposure in accordance with Table R301.2(3).
R905.2 Asphalt shingles.
The installation of asphalt shingles shall comply with the provisions of this section.
R905.2.1 Sheathing requirements.
Asphalt shingles shall be fastened to solidly sheathed decks.

This might where the contractor is telling him he needs to sheath the roof. However the existing 1X does not need to be removed to do this. It is possible the insurance may pay for the new sheathing if you show them it is required by code.


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## ICE

There is nothing wrong with a dimensional lumber sheathed roof.  No shingle maker has any issue with it.  The code stipulates solidly sheathed as in dimensional lumber or plywood/osb.


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## ADAguy

All good comments, however he did not mention the age of the building. My 1905 with space sheathing  and wood shingles (no underlayment and no leaks!) was reroofed 2 years ago. Removed the shingles, kept the space sheathing, overlaid with plywood, underlayment and new asphalt shingles; good to go for another 30 (+).


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## e hilton

jar546 said:


> It was common practice to have a clause in the contract that once the roof was stripped down, depending on what was found, plank roofs that were not already covered with plywood would then need to be covered in order to do a good job and provide a solid warranty.



Ahh ... the contract!  Right, if there was such a clause then the OP is probably stuck with the upcharge.  But its not required for warranty.  
And if the shingles are hand nailed, there wont be any nails in the gaps.


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## Wallace Stine

Jerry Hiatt said:


> Recently had hail damage to my asphalt shingles. The roofer has been tearing the old roof off and has found that the sheathing is dimensional lumber. Mostly 1x6's. He says it all has to be torn off and replaced with plywood. He says it is not up to code and he has no choice. At my expense of course. Any feedback would be appreciated.





Jerry Hiatt said:


> Recently had hail damage to my asphalt shingles. The roofer has been tearing the old roof off and has found that the sheathing is dimensional lumber. Mostly 1x6's. He says it all has to be torn off and replaced with plywood. He says it is not up to code and he has no choice. At my expense of course. Any feedback would be appreciated.



Your contractor is correct that decking would have to be installed over the board decking if gaps of 1/4" is existing. You are incorrect that you have to pay for this under you the terms of your insurance policy.


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## Wallace Stine

Mark K said:


> The IRC is for new construction.


The IRC is for new construction, and alterations, movement, enlargement, replacement, repair, demolition to name a few.


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## e hilton

Wallace Stine said:


> You are incorrect that you have to pay for this under you the terms of your insurance policy.


Wallace ... curious about why you are saying this.  Are you in the insurance industry?


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## Wallace Stine

e hilton said:


> Wallace ... curious about why you are saying this.  Are you in the insurance industry?


Yes, I’m a licensed Public Adjuster and insurance appraiser.

A homeowner’s policy is a policy of indemnification. Anything short of indemnifying the policyholder 100% for a covered peril is a breach of contract. The policy reads “We agree to insure the structure” not “we agree to insure a certain building component”. When coverage was extended to the roof assembly it was extended to the entire structure for the peril at hand.

Most policies exclude rot. The claim was not for rot. The claim was for Hail, a cover peril. Decking would fall under causation. Although it did not sustain a direct physical loss, it had to be replaced due to a deficiency to facilitate the repairs to the roof assembly that was damaged by a covered peril.

Keep in mind decking is part of the roof assembly per the ICC. 2015 IRC  added the term to definitions “Roof Replacement” to address this very thing.

Edward Eshoo from Merlin Law group has said it best. Here is link to his blog.

https://www.propertyinsurancecovera...lacing-roof-shingles-coverage-or-scope-issue/


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## Wallace Stine

jar546 said:


> There is no argument for this.  Your situation is not a code issue unless the shingle manufacturer installation requirements prohibit this.


 All manufactures installation instructions require decking to have gaps less than 1/4 inch. CertainTeed has gone as far and will not allow shingles installed over solid board decking over 6" wide, as the movement of any board wider will pull the nails out of the shingle. In addition to R905.2.1 addressing this very thing.


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## my250r11

It is my job to write the correction. It is not for me to decide who pays what. The issue shall be corrected before I will sign off.

If I worried about cost I would never write a correction. Every contractor & or homeowner this will cost me $XXX is the first thing out of their mouth.


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## ADAguy

That is why I have a "code" compliant & match "existing materials" replacement ryder on my 1905' Craftsman fire insurance policy.  
Also upgraded as to contents. Again, buyer beware of for what and why you buy your policy.


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