Thread: Plywood sheathing laid up wrong way

Plywood sheathing was laid up over the original strapping so they could install fibreglass shingles. On one side of the roof, they laid all the sheets vertically instead of across the trusses. I pointed it out to my client, not correct, but ......... so what? Does anyone think it is a problem?

I recommended a trim strip to cover the raw edge at the gable ends.

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I wouldn't call it out seeing as how the skip sheathing was left in place.

Originally Posted by John Kogel

Plywood sheathing was laid up over the original strapping so they could install fibreglass shingles. On one side of the roof, they laid all the sheets vertically instead of across the trusses. I pointed it out to my client, not correct, but ......... so what? Does anyone think it is a problem?

I recommended a trim strip to cover the raw edge at the gable ends.

JK: Spaced plank sheathing notwithstanding the plywood should have been installed perpendicular to the trusses. Additonally, drip edge flashing, and not wooden stripping, is required at the fascia.

Good morning John

Have run across this detail more than once. I have talked to a few supplyers and they all have the same comment, would rather not see it that way but with the 1x existing decking is allowed. I beleave this is caused by roofers doing carpenters work and not have the proper direction from with in the company. As for the metal drip edge, in many areas this is becoming a requiremnet of local building codes and standards of practice. It can be installed now but would have been easier at time of re-roof.

Have a GREAT DAY - Brad !!!

Additonally, drip edge flashing, and not wooden stripping, is required at the fascia.

Dripedge flashing is typically not required at the rake or eave dripedge areas. Last I heard, the only manufacturer that seemed to state that it was required backed off and stated that it was preferred, but not required. (Pabco based on memory).

A.D.M.: Can you show me where the requirement lies?

2006 IRC
R903.1 covers the requirement to install per manufacturers specs.
R903.2 (flashing- general)
R905.2.8 covers flashing for asphalt shingles

Thanks.

Originally Posted by Brandon Whitmore

Dripedge flashing is typically not required at the rake or eave dripedge areas. Last I heard, the only manufacturer that seemed to state that it was required backed off and stated that it was preferred, but not required. (Pabco based on memory).

A.D.M.: Can you show me where the requirement lies?

2006 IRC
R903.1 covers the requirement to install per manufacturers specs.
R903.2 (flashing- general)
R905.2.8 covers flashing for asphalt shingles

Thanks.

Brandon Whitmore,

Read what's left of this (linked below) entire topic string, check the references, then if you're still in the mood to "do a Tony" let us know.

Link: http://www.inspectionnews.net/home_i...flashing+gable

H.G. ,

That pretty much sums up both sides pretty well (as well as one far off side) It is still my opinion that it is not required. There's well respected individuals with opinions on both sides of the fence.

Do I think it's a bad idea not to use it: Yes.
Do I think it's cosmetic and serves no purpose: No
Do I use dripedge flashing on my own installations: Yes
Have I seen installations that don't have dripedge flashing work just fine: Yes
Have I seen installations with dripedge flashing that don't work: Yes

Do all inspector's interpret given info. the same:

H.G. : I'm not trying to battle this one out-- it looks like the topic has been beaten to death. I think that everyone should read the link you provided , study ARMA/ NRCA guidelines, as well as manufacturers installation instructions so that they can form their own opinion.

Is this house older with 24" oc 2x4s? If they aren't trusses, the added weight of plywood and shingles should be a concern.
If is is not, then describe what's there and move on. The horizontal purlins should suffice. Plus remember, 4 ply plywood has 2 plys perpendicular. 3 ply still has one.

JLMathis

In Florida, the drip edge is required. Specifically required.

In the IRC, it is required ... sort of ... mostly ... just not specifically stated ...

(bold and underlining are mine)
- R903.2 Flashing. Flashings shall be installed in a manner that prevents moisture from entering the wall and roof through joints in copings, through moisture permeable materials and at intersections with parapet walls and other penetrations through the roof plane.
- - R903.2.1 Locations. Flashings shall be installed at wall and roof intersections, wherever there is a change in roof slope or direction and around roof openings. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch (0.5 mm) (No. 26 galvanized sheet).

Does not the roof slope change from "sloped" to "vertical" at the edge of the roof covering?

Aaron,

That is not "wooden stripping" in that photo, that is the edge of the plywood, which, as I recall, is not allowed to be left exposed to sunlight or the weather.

The plywood should be installed perpendicular to its structural supports for the purpose of creating a diaphragm for the roof.

However, being as spaced sheathing was allowed for that purpose, the plywood installed vertically can only do some additional good, albeit maybe not a lot of good as its good would be dependent upon the attachment of the spaced sheathing to the rafters/trusses.

Plus, it is rare that plywood installed in that manner is attached as it should be attached.

Too many things 'not right' about it to allow it to pass without comment.

At the very least make your client aware of it being a potential problem when they become a seller and that YOU are not going to be the one 'passing money on' for the plywood having been installed that way, that they should address it for a credit and be prepared to to pass that money along to their buyer.

It could become a game of 'hot potato' and you refuse to be caught holding the hot potato when the game stops.

Thanks, all. Jerry, I called for "trim strip" at the gable, Aaron corrected me, "can't use wood". Duly noted. Shall specify "Drip edge flashing." Most roofers here don't know what that is.

Back to the plywood running with the rafters because the skip sheathing is still in place. Absolutely nothing wrong with it. That is no different than running 1x3 strapping on the ceiling joists before the drywall as all older homes (especially in the North) had. Not to mention the skip sheathing is certainly a lot closer than 16 on center or 24 on center as the roof framing would be. Once upon a time the rafters and ceiling joists would have been 16 on center. It made for a much tighter stronger home.

I thought drip edge is at the gutter.... isn't that rake flashing?

As for the orientation of the plywood over skip sheathing it would never make my report. When a seasoned group of inspectors (on this board) can't agree or site concrete proof that it's wrong (outside of Florida anyway ) there's no way it will ever burn you in the real world. Note the caviat of the real world... once somebody's got it out for you there's nothing you can do/should have done to stop them.

Running scared and writing up anything and everything that "might" burn you someday is not a home inspection... it's a 60 page report of disclaimers which is, unfortunately, what this profession has evolved into for many of us.

As long as the original board underlayment is there I wouldn't say anything about the direction the plywood is installed.

I would recommend installing the drip edge. It doesn't matter if it's code or not, or even recommended or required by the manufacturer. Having drip edge is the better way to do it. I don't inspect by code since code is MINIMUM requirements.

Technically the plywood sheeting should not be used on the exterior without some sort of protection. Painting it would look silly.

I'd be more concerned with the possible use of staples to secure the plywood sheeting to the old boards.

From the 2007 California Building Code.



1507.2.9.3 Drip edge. Provide drip edge at eaves and
gables of shingle roofs. Overlap to be a minimum of 2
inches (51 mm). Eave drip edges shall extend 0.25 inch
(6.4 mm) below sheathing and extend back on the roof a
minimum of 2 inches (51 mm). Drip edge shall be
mechanically fastened a maximum of 12 inches (305mm) o.c.


I realize that this is not from the IRC, and the CBC is based on the IBC.

At least this might be of some use to those inspectors in CA.

Originally Posted by Matt Fellman

I thought drip edge is at the gutter.... isn't that rake flashing?

Matt,

"Drip edge" is used to refer to either location.

"Eave drip" would be the comparable term to go with "rake flashing" if one wanted to separate the two into separate terms.

Originally Posted by Gunnar Alquist

From the 2007 California Building Code.



1507.2.9.3 Drip edge. Provide drip edge at eaves and
gables of shingle roofs. Overlap to be a minimum of 2
inches (51 mm). Eave drip edges shall extend 0.25 inch
(6.4 mm) below sheathing and extend back on the roof a
minimum of 2 inches (51 mm). Drip edge shall be
mechanically fastened a maximum of 12 inches (305 mm) o.c.


I realize that this is not from the IRC, and the CBC is based on the IBC.

At least this might be of some use to those inspectors in CA.

Gunnar,

Looks like Florida and California have that covered similarly - gotta be installed ... now if only the states in between would likewise address it ...

Originally Posted by Matt Fellman

I thought drip edge is at the gutter.... isn't that rake flashing?

Matt, a "rake" is for leaves. The parts of the roof are "the shingles", "the gutters", and the "saw-fits" (pointing up at that under part that's not slopey).

Originally Posted by Matt Fellman

As for the orientation of the plywood over skip sheathing it would never make my report. there's no way it will ever burn you in the real world.

Some clients wouldn't need to know. This buyer was a woodworker handyman type. I know he will see the flaw when he moves in, so I told him, in so many words, "I saw that, Do you think it's a problem? No? Ok, we move on then". It's a more basic CYA, which is to try not to miss anything they can claim you missed later.

Originally Posted by John Kogel

Matt, a "rake" is for leaves. The parts of the roof are "the shingles", "the gutters", and the "saw-fits" (pointing up at that under part that's not slopey).

Some clients wouldn't need to know. This buyer was a woodworker handyman type. I know he will see the flaw when he moves in, so I told him, in so many words, "I saw that, Do you think it's a problem? No? Ok, we move on then". It's a more basic CYA, which is to try not to miss anything they can claim you missed later.

Main Entry: sof·fit
Pronunciation: \ˈsä-fət\
Function: noun
Etymology: French soffite, from Italian soffitto, from Vulgar Latin *suffictus, past participle of Latin suffigere to fasten underneath