how to install gable vent over cedar siding?

Old 05-29-09, 02:40 PM
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how to install gable vent over cedar siding?

I am looking to install some gable vents since our house doesn't have any and the attic ventillation is terrible. The gables are horrizontal running cedar siding and I was just wondering what the best way to install the vents would be. I know I make a frame on the inside and then cut a hole from the outside, but does the vent sit on top of the siding or do I need to cut the siding so the vent sits flush? Also, do I need to install flashing or building paper and if so, where/how?
Old 05-29-09, 05:19 PM
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What other venting do you currently have, ridge? soffit? Gable vents could be in conflict with ridge vents, so one or the other.

As for the siding, I have only done a couple of new construction cedar jobs, but my guess would be to remove enough shingles to flash to opening properly, install the vent, and then re-shingle. If you carefully remove the ones in that area, you should have enough to fill back in and they will match.

Old 06-20-09, 08:09 AM
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The answer depends on the type of vent you have. First off Bud brings up a very good point about conflicts of ventilation and I suggest checkout air vent's website to learn more about ventilation short circuiting. Air Vent

Assuming you've made sure the vent won't interfere with the existing ventilation... The vent may come with a template, or probably not. take a piece of paper and trace the outline of the back of the vent, then use that to trace onto the house where you want the vent to be. I am assuming the siding is a horizontal bevel type siding for the rest of this, correct me if I am wrong.

Cut an opening the size you traced through the siding and through the backer board but don't cut the studs. Next cut the siding, but not the backer board 3 1/2" larger in each direction. Assuming the vent has a nailing fin, nail the vent onto the backer board. If this were my home I'd use some self adhering flashing around the nailing fin, start at the bottom. Then I'd install some 1x4 nominal lumber trim around the vent to cover the nailing hem.

I wouldn't worry to much about the framing and worst case scenario only one stud will cross the vent. If you reallyr eally don't want this, you'd frame it just like you'd frame a window.

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