Worried about vent slot wider than specs

We just had our roof reshingled as part of a larger remodel. I am sick about water intrusion at the moment due to an unrelated leak we had earlier.
Anyway, the roofer installed a Shinglevent II ridge vent, which is 13.8" in total width. We have a 1.5" wide ridge board, and the manufacturer specifies that the slot for the ridge vent should extend .75" on each side of that, for a total width of 3". My contractor instead made a slot that’s a total of 5" wide (1.5" on one side of the ridge board and 2" on the other). My roof deck is from the 1950s, and made of 5.5" planks. I think they just pried of the top plank rather than cutting. Looking up from the attic, it looks HUGE. I am so upset about the possibility of leaks, but also worried that if I insist it be repaired more problems may result.

Here’s my question. Shinglevent makes the same vent in a 10" wide version and an 11.3" wide version (the Shinglevent II-7 and Singlevent II-9). These narrower versions call for the same 3" wide ridge slot even though they have significantly less overhang beyond the slot. Given these facts, is it safe to say that, while technically wrong, I should be fine? Has anyone else been ok with a slot this wide on the standard Shinglevent II?

As long as the slots are covered by the vent, you should be ok. The main concern is that the air flow be balanced so the vents deliver the performance you want and need. The square inch total opening should be equal to the total square inch opening of the eave vents (or at least close).

Thanks. This is a really wide vent, so that’s reassuring. On the other hand, the manufacturer insists it will leak. The slot could be 8 inches and still be covered by the vent, but it just seems wrong to have than kind of vulnerability in my roof.

What’s the roof pitch? anything under a 6/12 and I’d worry about wind driven rain and/or melting snow with over sized slots like that.

It’s 4/12. Sounds like I need to get it fixed. Are they going to be able to reuse the vent after they pry it off? Should a course of shingles be replaced and new wood put up? I’m trying to figure out what I need to be looking for and asking for. I’m of course going to be afraid they won’t do it right and/or will make it worse.

Reuse the vent? Maybe. Shingles replaced? Yes. Wood fixed? Yes. Good luck. :slight_smile:

Yes, it does matter. Especially in Erie, PA. We get a large amount of snow.

When the ridge vent opening is cut wider than the spec. it causes the top of the ridge vent/cap
to be/become flat. When it is flat, water can sit/puddle on the ridge and get in between the ridge cap
shingles and leak. It can take years for the ridge vent and cap to flatten out. It eventually does.
When it does…it will leak.

We have repaired dozens of ridge vent installation errors.

I have seen far too many ridgevent s leak because of this. It needs replaced. They may be able to re-use it but since they’re going back on “their dime”, I would think they’d want to get it done as quickly as possible so the extra time spent to try and save the old stuff would just not be worth it IMO. I’d bring new rvent and cap to speed things up

Some attics are hotter than others for various reasons. If you had an extremely hot attic before this was done, it may actually be better.

Many factors are at play.

I don’t see it causing a problem the way it is even though it was not cut exactly to specifications.

As far as flattening out is concerned it depends on how it was installed.
On a 4/12 slope, I nail one side and then push and hold the other up a bit before nailing to prevent flattening. Plus I do not sit on top of newly installed ridge vent.

I’m new to the site and I realize this is an older post but since it’s relevant to me I thought I’d give it a try:
I had the same thing happen- wider slot because ridge vent slot was cut from edge of ridge beam. I was wondering how original poster made out.
He had made a good point about the shingle vent ii in 7” and 9” widths calling for the same slot size even though the width is 5” and 3” less respectively. Recognizing that fact, it’s hard to envision that only 1” to 1-1/2” more in slot width on each side would make the difference on water intrusion. Also, these panels are fairly rigid and testing on the ground seemed to indicate that it would take a lot of weight to flatten the ridge vent permanently.

I dont install ridgevent if there is a ridge board
Because the cut would be too big.

I like my cuts at 2 1/2 inches, 3 inches maximum