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Gable vents in aluminum siding

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I have to cut in some gable vents in a building that has aluminum siding on it. Does anyone have any suggestions on the best way to cut these in?
Will I need to take down each individual piece and cut it or is there an easier way to cut these in without taking down any siding?

(post #178104, reply #1 of 9)


I think you had this question posted twice. I answered it but cnnot find the posting, so here goes round 2:

Don't remove the siding. Buy the type of vent you want to install first. It should have directions with it. A good type of vent to purchase is a 2 piece version; which contains a frame that gets srewed onto the wall and then a snap ring piece that simply snaps on. This type is usually made from vinyl and the construction is similar to "J" channel construction which allows the siding to fit around the vent and any rain water from the siding will drain around the "J" channel framework.

To cut through aluminum siding, use a sawzsall (recipricating saw) with a bi-metal blade. You also could use a jigsaw with the same type of blade.

You may need a pair of tin snips to fine tune your cutout.

Just make sure nothing is behind the wall where you are planning to cut (electrical/plumbing lines, etc.).

Don't forget to caulk where needed.

Good luck.


(post #178104, reply #2 of 9)



In the absence of one. . . Fred Lugano. . . forget the gable vent. If it is one thing (and there are few) that I agree with both him and Gene Leger on is that gable vents are a no no.


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"More than any time in history mankind faces a crossroads. One path leads to despair and utter hopelessness, the other to total extinction. Let us pray that we have the wisdom to choose correctly."

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(post #178104, reply #3 of 9)

To expand on what Joe said, I believe that it is a generally accepted among the "well read" building community that gable vents do a poor job of ventilating, i.e. uneven air flow across the underside of the roof deck. Further, they have the added disadvantage of possibly emitting wind driven rain and snow into the attic space. What, you say you live in the desert where the average yearly rainfall is .5"?! Well OK, the first point is still valid.

To learn more about air circulation through the attic, go to this Certainteed web page.

Talk your client into ridge vents.

PS: Joe: Fred would be so proud of you!! ;^)

(post #178104, reply #4 of 9)


I would also not recomend putting in a gable vent, for the aforementioned reasons. If you must, removing a few courses of siding, installing the vent, and re-installing the siding is the least frustrating way to do it. Setting a plank up in front of the area makes it real convenient.

Red dog

Gable vents (post #178104, reply #5 of 9)


I have a question along the lines of this conversation.  I'm finishing a half story on a house with no overhang (built in '53).  I was going to install vents lower on the gable ends, right and left, to vent the space behind the knee-wall.  Then add vent chutes between the rafters from behind the knee-wall to a ridge vent.  Would this be acceptable?



Todd (post #178104, reply #6 of 9)

The formula for sizing the low gable vents is (I'm not that smart , you can look it up).

but even with the proper area of vent, you'll have diminishing air flow the further you get from the vents.

If you insulate and seal the ceiling of the rooms below, it can't hurt and most likely would help.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


"Acceptable" is probably (post #178104, reply #7 of 9)

"Acceptable" is probably beyond reach in your situation, but it would likely be an improvement.  Remember to air-seal the ceiling below and, of course, the knee walls (especially electrical outlets).  You probably should have some sort of "sheathing" on the outside of the knee wall (if you don't already have it) -- exposed fiberglass is a very poor insulator.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

gable end vents (post #178104, reply #8 of 9)

What if you live in a cold climate? Are gable vents better to have to pass some ventialtion thru when ridge vent is covered in winter yet you have side soffet venting?

Depends on where you live.  (post #178104, reply #9 of 9)

Depends on where you live.  Around here ridge vents are only covered for a day or two after a heavy (6"+) snowfall, even though most of the roof is covered for much of the winter.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville