Broken OSB under Ridge Vent - Advice Needed

Just had my roof replaced last week. Today, I was cleaning up in the attic when I noticed what appears to be a problem. Whoever decked the roof 17 years ago installed the 1/2 inch 4x8 OSB decking in such a way that they ended up with a 4 inch wide strip of OSB on one side of the ridge vent slot. The original roofer managed to install the vent without breaking the OSB strip, but the 4 inch wide strip has now been repeatedly broken by the large nails used to secure the new ridge vent. On a 30’ridge the are at least 7 complete failures between rafters and at least 2 places where the OSB strip is obviously cracked. 3 of the complete failures are between adjacent rafters.

No leaks now after a weekend of rain, but this can’t be good in the long run, right? At some point won’t things sag and loosen up enough for wind blown rain to get between the ridge vent and the poorly/un supported shingles?

I’m thinking that this needs to be fixed now, and that the only way to fix this is to remove the vent, and repair the decking by cutting the sound decking back far enough to piece in a section of OSB wide enough to be strong.

Or am I worrying about nothing?

I need some advice before I call the roofer.


Short term, no problem.

Long term, big problem.

Call the roofer asap. He should be more cooperative if you call now rather then later. Just remember unless the owner did the actual work, he wouldn’t have know unless his worker told him. Could be an honest mistake.

You rightly have concerns. It probably isn’t too much of a concern when the weather is cold and the shingles don’t “mold” into the depression allowing water under the vent. When you have a chance, a 2x4 under the cracked OSB, nailed to each rafter, should take care of the problem by supporting the OSB. The down side is the 2x4 will block some of the air movement, so make sure it is installed flat. Now (winter) is not a good time to be taking off the ridge and adjoining shingles to replacing the OSB.

This is one of the reasons why i do not like ridge-vent.

Ridge-vent really does look good on paper though!

Real world? not so much…

Is it really the roofers fault?
You sound like a smart fellow.
You could do it yourself!
I beg your forgiveness if you are handicapped or older. Or uncomfortable with some things.
I think you can do it. You’ve already proved that by going up there in your attic and used your brain and came up with some very compelling reasoning.
Which you discovered and are correct!

but again, Is it really the roofers fault? really?

Get an 8 ft 2x4.
Cut three pieces 22 1/2 inches fat!
Meaning not 22 3/8.
A solid 22 1/2 or slightly fatter.

Take a hand full of 12ds and nail those supports under the broken 1/2 inch you see.

It wont be a problem nailing them in because they are going to fit tight without a single nail.

It Doesn’t have to look pretty or be perfectly paralleled with the ridge. Try to support the cracked board while missing any nails nailed through it from the top.
You want to try not to push any nails up.

You can do it!

Keep in mind with all this, NO one should ever be standing on your ridge anyway! We all know there is a big hole there and we don’t want to crush it…sigh.


roof-lover wrote…“Is it really the roofers fault?”

Actually it is the roofers fault. Read the post. The op said it was not like that before the roof was stripped and replaced. The new roofer probably stepped on it or tried to break a bundle over the ridge and cracked it. I have done that before but have always replaced the damaged area.
Have the roofer come out to fix it or as stated above you can install 2x4 material between the rafters.

Just my .02


Thanks for all your responses. I’m not angry about this, stuff happens. I just want to make sure I end up with a sound roof after having spent the money. I thought about bracing the broken OSB from below as has been suggested here. The problem I see is that the OSB was clearly broken by the long nails, which are in contact with or partially through the OSB. The nails have forced the OSB down by as much as 1.5 inches where it is completely broken between rafters. So for me to force the broken OSB back into place with 2x4 braces would appear certain to force the nails up through the shingles on top of the ridge vent.

I’m wondering if the roofers reading this would consider it an acceptable repair for my roofer to brace as suggested here, and then replace the shingles on the ridge where needed due to the nails being pushed up? Perhaps this would be a simple cheap way out for both of us.

Perhaps this would be a simple cheap way out for both of us.[/quote]

The cheap and simple way would have been for the roofer to notice the problem and block under the osb before adding the shingles. IIRC the APA association calls for blocking on any sheathing less than 6 inches wide, and they don't recommend any sheathing less than 12 inches wide?

I’ve only seen it on Mobile homes. We just drop down about 24" and cut it out and install a new piece. No roofer can honestly say they missed that. Even if the underlayment was left on after the tear off. You step on that area and you would have sucked wind for half a second or shorter.

If it’s something you would like to repair, then add the 2X’s if you can reach the ridge pole from the attic side. Otherwise, your looking at removing the ridgevent, cutting out decking and installing new shingles.

The roofer probably didn’t see it when he bid the roof, but really needed to be fixed when it was torn off.

well im sure thees are not aluminum
ridge vents that get screwed into the deck
rather than nailed with some long nails.
(search aluminum ridge vents online.)

i do not like ridge vents that get cap shingles
nailed over them.

how can i say it in my allmighty tounge

" they are just stupid"

get yourself some aluminum ridge vents
instead of what you have.


Rippings are to never be under a predetermined width, dependent on the thickness and span of the trusses. You can check how your local code varies depending on your snow loads and wind conditions. When I write a spec for a roof, I never allow less than 24 inch rippings and they must be located at least at a point 2/3 of the way up the rake of roof toward the peak. Full sheets must be used at the ridge and at the eave. I also require a galvanized metal C-Channel at the ridge vents for reinforcing.

UNFORTUNATELY, most design professionals don’t inspect or provide oversight on small to medium projects (and even some large ones). I recently looked at at roof that had it’s sheeting completely removed in straight line winds. NO CLIPS, NO 8D RING SHANK NAILS, NO ADHESIVE… nothing left but roof trusses! Sadly, many of the jurisdictional municipal inspectors in many areas do drive by inspections on their way to the bank, as there is no legal recourse for neglect in the way they do their work.