# roof decking replacement



## Sifu (Dec 11, 2014)

IRC requires shingles to be fastened to solidly sheathed decks ('09, 905.2.1).  Not much guidance there, and not a lot from manufacturers that I can find either.  Have any of you guys found or developed any more specific criteria for when a roof deck should be replaced?


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## Min&Max (Dec 11, 2014)

Lets try the following--- the roof deck shall be replaced when the structural integrity of the roof sheathing has been compromised by weather elements, insects, age or disaster such as fire or earthquake.


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## ICE (Dec 11, 2014)

I thought that most shingle manufacturers required a minimum thickness for sheathing and it is 1/2".  As to when does it need to be replaced....that's not in the code other than the word "solidly".  You make the determination if the sheathing will support a fatboy roofer and hold nails.


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## Min&Max (Dec 12, 2014)

I do not recall ever seeing a sheathing thickness called out by a shingle manufacturer. The sheathing has to be rated for the span between rafters and that can be as little as 3/8" @ 24"o.c. ---not that I would ever advocate for that. Typically everything I see is 1/2" OSB @ 24"o.c. and clipped. On my own home I went 1/2" OSB @16"o.c. and clipped which accounts for it feeling like walking on a concrete driveway.


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## mtlogcabin (Dec 12, 2014)

> Have any of you guys found or developed any more specific criteria for when a roof deck should be replaced?


You do not have to remove the existing roof deck material if it is not damaged or water soaked. Just install 3/8" OSB or Plywood over the  existing skip sheathing and you comply with the manufactures installation instructions.


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## Sifu (Dec 12, 2014)

Some manufacturers do include a "recommendation", usually 3/8 plywood, 7/16 osb or equivalent.  That is easy enough to determine.  The pickle I find myself in is in the word "solid".  Case in point:  I was scheduled to conduct a final roof inspection but when I arrived I was asked to evaluate the sheathing.  The existing shingles had been removed and the house was tarped.  The contractor and homeowner wanted me to cite the sheathing so the insurance company would cover it.  Right or wrong I try to stay out of that type of transaction, and tried to avoid getting involved in this one.  I advised them that if I make that call it is irrelevant who covers it or who pays for it.  I explained that often I experience "soft" decking after the shingles are installed and that as long as the roof holds my concentrated load it is not an issue.  This has been the practice of the departments I have worked in out here and frankly most homeowners would go ballistic if I mentioned replacing the roof sheathing.  Well, they insisted so I did go up and I found that it was indeed bad, the worst I have seen.  So I wrote a correction.  Subsequently I received a call from the insurance adjuster who also observed the roof and agreed.  Today I got a call from the homeowner saying the insurance company won't cover it as it is considered normal wear and tear on a 30 year old structure.  I told them that they now are the proud owners of a correction to replace the unserviceable sheathing and as I had stated already, it didn't matter who pays for it.  This was just a reminder for me that I don't really have a consistent practice for when a roof deck must be replaced.  Probably half of the roofs I inspect are on homes that were sheathed 30 years ago and if the truth be known probably wouldn't pass the "solid" criteria today.  So I am curious about what others experience and how they handle it.  FYI, a tremendous hail storm came through a couple of months ago and as a result thousands of roofs are being replaced right now.  We get the decking question pretty often.


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## cda (Dec 12, 2014)

I thought insurance companies do not normally cover the decking

I know mine did not

How about requiring replacement when the third new roof hoes on ? Not sure how that could be tracked


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## mtlogcabin (Dec 12, 2014)

this is all they need to do for shingles


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## Sifu (Dec 12, 2014)

My default position is to assume the insurance company won't cover anything, that way I don't get burned.  In this case, the h/o wanted to use me as a tool to get the insurance company to pay.  I told them that isn't a good idea and I don't like being put in that situation and more importantly that my findings would be based on my own judgement regardless of what the insurance company might do.  I told them if THEY thought the decking was so bad then THEY should replace it, they didn't need me.  But they wanted to try and get it payed for by the insurance company as part of the storm damage.  Now, since I did observe the sheathing to be in such bad shape they have no choice, will need me to sign off on it and THEY have to pay for it.  I think their plan backfired.  (Tried to upload a pic from my computer but it failed)


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## ICE (Dec 12, 2014)

So I take it that you don't normally do a sheathing inspection prior to the roofing being installed.  Why would the condition of the sheathing be an issue at a final inspection?


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## Sifu (Dec 12, 2014)

Correct Ice, we do not do a sheathing inspection when it is a tear off and re-shingle.  And, normally the condition of the sheathing does not enter into the equation at a roof final for a couple of reasons, mainly because we can't evaluate what we can't see and unless we literally start stepping through it the assumption is made that it is sound.  In some cases, like this one we were asked to evaluate it prior to shingle installation, which has turned into a problem just as I anticipated.....why I tried to excuse myself from the situation.

Do you do sheathing inspections on a tear off and if so what criteria do you use?


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## JCraver (Dec 12, 2014)

I do sheathing inspections here, and I just use my own judgment/common sense.  If it's bad, I tell them they have to replace it.

My predecessor did not do deck inspections.  Most of the roofing contractors who work in our little town wish that I didn't...


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## Sifu (Dec 12, 2014)

JCraver said:
			
		

> Most of the roofing contractors who work in our little town wish that I didn't...


Imagine that


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## ICE (Dec 12, 2014)

Sifu said:
			
		

> Do you do sheathing inspections on a tear off and if so what criteria do you use?


There's your 3/8" plywood:





If the plan is to install roofing over an existing layer of roofing, I go look first.





Every now and then I have to say that you can't put a roof on that because it's not supposed to be there.





Sometimes I will suggest that more ventilation is in order.





It's a good idea to see what the roofer is up to.





You run into the darnedest things.





As far as your question about what criteria do I utilize when inspecting a roof deck....I pretty much wing it and there's lots of things to consider.

Fewer than one in fifty is a problem.  We used to also do an in progress inspection...Los Angeles doesn't do any inspections.


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## Paul Sweet (Dec 13, 2014)

I believe the requirement for solidly sheathed decks isn't how sturdy the sheathing feels, but to prohibit skip sheathing, which used to be common for cedar shingle or metal roofs.


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## JBI (Dec 16, 2014)

That next to last picture above - the extended rafter tails - I caught a guy replacing a balcony like that... Though he did leave 12" to 18" of the original cantilevers to scab on to. D'OH

On the OP, yes solidly sheathed is either panels or un-spaced boards as opposed to spaced board or skip sheathing. Descriptions are one chapter back. The 'inadequate base' language in the reroofing section requires an exercise of judgment by the Inspector/Official.


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