"continuous ridge vent" ... what does it actually mean?

My plans specify "Continuous ridge and soffit vents", but the builder didn't extend the vent all the way across the ridge.

Before I push back on the builder for this, is there a legitimate reason to do this? If not the full length, how did he decide what length to install?

Usually full ridge vent means along the entire length of the ridge, maybe stopping 6-12" short of the eaves.

My guess, he ran short.

There are calculations for this on internet. Comes down to a fairly equal and balanced upper ridge vent N.F.A. as compared to the soffit intakes N.F.A. net free area. This can be complicated with fire blocking and closed soffits and jurisdiction's interpretation.

Does the roof framing change where the vent stops? (Like a vaulted ceiling or rafters)

We run the full ridge except for the last 2' on each end.

The roof sheathing, we stop it about 1" from the peak on each side. We block the trusses flat framed at this edge. This ensures air flow and a positive surface for nailing the vent on. Roofers do not always just nail at the truss location. We have had ridge vents ripped off with high winds. The solid blocking has eliminated that.

jack stand said:

Does the roof framing change where the vent stops? (Like a vaulted ceiling or rafters)

Click to expand...

No, and what's more, the same roofer ripped the peak open all the way to the end, as if he was going to run the vent the whole way, but then didn't install ridge vent all the way to the end. Further supporting the "ran out of material" hypothesis.

larry4406 said:

We run the full ridge except for the last 2' on each end.

The roof sheathing, we stop it about 1" from the peak on each side. We block the trusses flat framed at this edge. This ensures air flow and a positive surface for nailing the vent on. Roofers do not always just nail at the truss location. We have had ridge vents ripped off with high winds. The solid blocking has eliminated that.

Click to expand...

You sound like a good builder that uses common sense and understands that cutting corners to have a few pennies is false economy. We don't have any of those here. These guys will go out of their way to cut corners in ways that are more malicious than lazy.

Assuming that he did it based on intake/output calculation and because he couldn't/wouldn't like to increase intake (soffit vents number and/or size), I'd still wonder why he chose not to place the vent in the middle of the ridge or use two vents toward the opposite ends and maybe one more in the middle. IMHO, this would eliminate dead spots and ventilate the attic more uniformly.

I'd start with checking if the input/output calculations for your attic were correct.

I don't know what, if any, calculations were used on my building, but the vent stops about 3' back from the edge. I didn't know that might be something to discuss with the builder, so never brought it up. I just assumed it would go closer to the edge.

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A couple decades ago, I had a roofing co. w/a good reputation do a roof replacement on a 1600 sq. ft. ranch, including the installation of a continuous ridge vent. It did not go to the very end of the roof on either side.

I just had the same company install a replacement roof. In So. FL, Miami-Dade County and Broward County are in what's classed as a High Velocity Hurricane Zone (HVHZ). That's the Miami-Ft. Lauderdale area. I carry homeowner's liability, a flood policy, and a wind-only policy. The wind-only policy company said they weren't renewing my policy. Evidently, they think the existing roof was at its service limit.

I went with the same roofing company, and when I inquired about installing another continuous ridge vent, the G.C. said they don't use that any more, and they install multiple 'goose-neck' vents of galvanized metal instead. They give better service life, he said.