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Two part question: big or small vent size, and parallel or perpendicular to house?

I'm going to install almost 40 of these soffit vents around my house. All the vents at my Home Depot are 16" wide, so when I hang them parallel to the house (traditional), the corners all fall over a groove. Not ideal.

The 16" vent width matches the 16" 3-panel metal sheet width, so I can offset them and have vents overlapping panels. I'm concerned I'll be forced to make more and smaller size cuts with this strategy.

Another option is to install them perpendicular to house. It looks kind of funny, but both sizes vents would fit out of grooves better. But I'm afraid it'll scream "doesn't know jack" to everyone, especially potential buyers.

Also, should I use the bigger or smaller size, since I'm installing them under every other 16" attic bay? Bigger vent costs about 90% more.

I'm might use the smaller vents perpendicular to house, but what do you think? Thanks in advance.

BTW, I can get the smaller vents in white also. BBTW, I forgot pic of bigger size perpendicular to house, but it covers two of the "bay" sections, with a groove running down the middle so the middle screws might be a hassle.

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Were I you, I"d go for the big full size soffit panels

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ALL the way around.

You pretty much can't have too much attic ventilation - you can have too little.

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+1, this is essentially the right answer, but from Kirk's earlier question, it doesn't appear to be an option. – BMitch Oct 29 '11 at 1:57
I think that he's looking in the wrong area - at ductwork/vents not siding. Home Depot carries the stuff I'm recommending. – The Evil Greebo Oct 29 '11 at 12:51
it's not that he can't find it, it's that he's refusing to replace his soffits to save a few bucks. Thing is, doing it wrong the first time, and then fixing the mistake later, will be more expensive. – BMitch Oct 29 '11 at 14:34
Evil is right on this one. Tear out the wrong soffits and replace with continuous soffit vents and proper-vents in the attic. There is probably insulation over the soffits already and the vents pic'ed in question are absolutely the wrong way to go and won't work if there is any insulation over the soffits. The right stuff is not that expensive, just have to cut it to length, slide it in and lock. Perhaps the other option to vent the area are gable end vents??? – shirlock homes Oct 29 '11 at 20:55
I hear you and know it's better, but saving a few bucks now is a bigger factor than I can communicate. Life is a squeeze sometimes and do the best with what can be had. I'll check again at Hodo, I was looking in the aisle across from the rain gutters, in roofing area. I'll ask a worker for this specific item and compare it. I already have gable vents at both ends, and five 12" vents spaced along the ridgeline. Thanks for the advice! – Kirk Hings Nov 1 '11 at 22:12

Given the options (and I still agree with my earlier post and Greebo's answer of "none of the above, replace your soffit with a vented version"), I'll go with option B.

Some other thoughts:

  • Get a good seal between the vent and your existing soffit, which would won't be able to do with your first or last option.
  • Make sure there's a screen of some kind in those vents to keep out the bugs, bees, and anything else that would enjoy making a home in your attic. This is why I suggest you get a good seal to the soffit.
  • Make sure the insulation is not touching the roof and that there's a clear path for the air to flow from the soffit to the ridge vent.
  • Finally, if you can get a plastic soffit vent, I'd go for that. You'll reduce the risk of corrosion and it will blend in better.
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Good point about the seal, that would tip it to the 4" turned perpendicular to the house. They are all metal at my Hodo, and all screened behind the vents. I may apply a bead of sealant after reading about bugs 'n bees. I've already been combing attic insulation back from the eves. – Kirk Hings Nov 1 '11 at 22:24

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