Do gable vents need soffit vents too?
Someone else’s question about soffit vents got me thinking about the project I am no longer involved with, but last time I talked to the guy running the project, he was talking about putting 1×4’s on the soffit. When I asked about venting, he said there’d be a big gable vent; but I was thinking, don’t gable vents just provide an outlet for the air and don’t you need an inlet at the soffit? I may have asked this before, but in my rambling post about other mess-ups on that job, so if it was answered, I don’t recall what the answer was.
[I’ve wanted to drive by and look at what they’ve done since I stopped working, but think maybe I should just let sleeping dogs lie–I went by the morning they were to start work again at about 9:45 and not a soul was there, so I dropped off the joist hanger nails (for a header) in a plastic bag labeling them as such and took off. The T-111 siding was all piled on saw horses and covered with plastic sheeting, ready to be put up. Hope they didn’t use the joist hanger nails for that purpose!]
Replies
No. Gables do not need soffit vents.
There should be a balance between the soffit vents and ridge vents.
The old fashioned triangular gable vents have been shown to be detrimental to the attic ventilation system.
Thanks--I guess the guy was right on this one!
Typically with a gable vent system, one end becomes the inlet and one end the outlet. Not a perfect system by any means.
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Thanks; when I thought about it I realized that (air flow in at one gable vent, flow out at gable vent on opposite side or roof), but then thought that this particular roof is on an addition and there is no "other end"--there is a gable at one end of the addition, and at the other end, the roof meets the old roof at 90 degrees and there are valleys. At that end, the new roof is framed on top of the old (so attics aren't joined, so no flow of air from old to new). I am afraid from what I've seen, that ventilation (lack of) will be low on the list of potential problems!
I've seen lots of houses with both ridge vents and gable vents. But, that's not correct, is it?
Not if there are also soffit vents. What I learned in a builder's license class was that adding gable vents will "short circuit" the flow of air from soffit to ridge and will actually make it not vent as efficiently. One or the other system, but not both. In the case I was describing though, there didn't seem like there would be "flow" because the other end of the roof was closed.
Sort of like if the wind is blowing from east to west and you open windows only on the east side (or only on the west side) of your house, versus opening them on both sides. Of course, soffit and ridge is like opening windows on first floor, and them opening the door in the starirway and opening windows on second floor to create a "chimney effect."
Also the vents at the eaves/soffits help vent the attic down low rather than allow the upper air of the gables to just blow through.