Roof ventilation question

[vanvanvanvan]

I got some great advice here about insulating my detached garage by building a ceiling with insulation, and leaving the attic and roof space as is, in terms of no heating/cooling. I'm about to dig in on that project, and was looking at putting in insulation baffles before the insulation. The garage is a square with a 4 sided roof that peaks in the middle, and there are two vents up at the peak.

But today I realized that on the eaves, there is no soffit, or any other substantial air gap that would let air in. Is that a problem? If it isn't, would I still install baffles at the eaves before putting insulation there?

I was planning to get some 1 x 4 x 12's or similar to string across the limited existing joists to then be able to put drywall panels up, with insulation above it.

Thanks for any help!

 

[Chris705]

Yes - if you plan on insulation and heating/cooling you ideally want to add soffit vents to go along with the two roof vents (I assume these existing vents are near the top). This is also important to keep your roof cool in the summer & not cooking your shingles. I would use baffles in each rafter bay to keep the roof as cool as possible. Add soffit vents in total area as needed to match the area of the roof vents. 3” round soffit vents in number that equals the area of both roof vents.

 

[Kaizen]

What does your roof look like with no soffit?


Sent from my iPhone using Tapatalk

 

[ford33]

In recent years, attic venting has evolved and there are many designs now considered acceptable. You need to decide how you want to use the space above the garage ceiling and then decide which attic vent design to utilize.

You will read a large number of responses from people with different opinions. Realize that there is no one best solution. You should do your research and decide what solution is best for you and implement it. Venting varies with climate and roof design and space utlization.

Attic ventilation can range from 1. No venting in the attic and make it an insulated no flow box, 2. vented attics with soffit and ridge vents with A. tight no holes ceiling with minimal air leakage from living spaces into the attic and lot's of insulation on the floor of the attic and no insulation on the rafters B. rafter insulation typically spray foam so attic is sealed in spray foam.

Why did you install two roof vents on your hip roof? Was that a design decision or an afterthought? Was a venting airflow calculation done to determine two vents are sufficient? There is a simple calculation to determine number of soffit vents vs ridge vent area.

 

[LaneRover]

It will probably help if people know where you are.