Gable vent question....

[chrisexv6]

My attic has a gable vent at one end....the other end has no vent. We have soffits in the house, and I believe they allow plenty of intake air (when we had the house resided, the soffits were done using "vertical" vinyl siding, running perpendicular to the house.........the end channels of the siding are in an aluminum j- channel, but are not sealed so essentially we are getting air intake from wherever there is soffit).

The gable vent had a powered motor on it, but I believe its dead (I flick the switch on even on the hottest summer days and it doesnt kick on). Ive been advised NOT to replace it with a new one. My issue is that the gable opening is allowing quite a bit of air *into* the attic (as evidenced by the very dirty fiberglass insulation below the gable opening).

Is there any louver type setup that can be installed that would basically open with the heat exiting the attic, and close when there isnt enough heat flowing out?

Im thinking the correct way to fix it is install a ridge vent and then just seal off the gable opening. But I was just wondering if there was a temporary quick fix until I can get a roofer out.

Thanks!

-Chris

[trader4]

Why are you worried about air exiting the gable vent? That's exactly what it's supposed to do. And if you go with a ridge vent, that's sure going to be bigger and open all the time.

Going with a ridge vent is probably the best solution. Until then, unless you have some specific problem that you failed to mention, there is no need to do anything else. Personally, I would not bother closing off the gable vent when you install a ridge vent. IMO, hot air rises and it will likely go out both the ridge vent and the gable vent.

[chrisexv6]

Actually the only reason I got to thinking was because we had a blower door test done on the house, and of course the testers went up into the attic.

The duct and chimney chase is not seal in basement or attic, so they suggested sealing it. They suggested against replacing the motor for the powered gable vent, and then saw the dirty insulation and summized (sp?) that air was coming INTO the vent, instead of just out. Now Im guessing some air coming in might be normal. I wanted to minimize that amount of air, because I have a feeling its then getting into the bathroom directly below the gable vent. The bathroom floor and bath tub are always cold (tile and cast iron usually are cold, but these are freezing), and Id like to do what I can to remedy that.

Perhaps Id be better off pulling up the insulation in that area of the attic and seeing if there are any drain/vent openings open to the bathroom walls?

-Chris

[tmurf.1]

Do you have "vented soffits" or just loose soffits? Ventilation is a very important issue in attics and often overlooked. You really need air to move from the soffit to the gable vent so you might want to install some soffit vents which are little one inch aluminum louvered discs which can be poped in easily, but the ridge vent is the best answer for the top. You can get lots of good info at the website of "certainteed products".

[nicksanspam]

Sure. You might use a few 8"x12" $12 automatic foundation vents that open their louvers when outdoor air is over 60 F and stay closed in wintertime to keep the attic warmer and lower heat loss from the house. A larger opening might have a single passive greenhouse sash vent, eg a Thermofor or the $19 Harbor Freight equivalent.

Nick

[chrisexv6]

The new (vinyl) soffit material was installed covering the existing (wood) soffit material. The existing wood soffits had soffit vents already in them....they werent closely spaced, but they were just little discs (more like decent size rectangles). The attic doesnt get overly warm in the summer, nor do the 2nd floor room ceilings, so it seems the ventilation is working.

I just figured a ridge vent would let less direct air in compared to a gaping hole at the end of my attic :) and that would help keep the upstairs a little warmer (assuming cold air is flowing in thru the gable and making its way past the insulation and then into any electrical/plumbing/HVAC opening).

-Chris

[Joseph Meehan]

You want to let air into the attic, just as you want to let it out. You want to do that all year long. If the wind blows some air into the gable end, that's fine. Actually it is good.

They were expressing some issue with the possibility of air coming up (or down) the gap at the chimney. That may be a totally different problem, but if anything it would mean you want more not less ventilation in the attic because that is likely to be warm moist air coming into the attic and less ventilation would increase the possibility of too much moisture building up in the attic and causing damage or mold issues.

[chrisexv6]

Thanks for the replies.

Yes they were concerned about the open chases for chimney and ducts. Ive gotten an estimate for them to seal it all up (as best they can) and will most likely have them do it (the 2nd floor to our house was added on, so the chases are kind of a mish-mash......if they were simple I could probably seal them myself).

I was just up in the attic looking at the area under the gable vent.....the first layer of insulation is dirty, but there is a second layer underneath that is fairly clean, albeit a little compacted (Im assuming its pretty old by now, maybe 20 years?). I might gut the insulation in that area, check for sealing at the plumbing and heating vents, and then put new insulation back. If the gable is really making air get into the house, at least I can minimize it by those little steps.

-Chris

[Joseph Meehan]

The existing insulation is likely 95% as effective as the day it went in. Don't dump it. You do want to seal those plumbing and heating accesses and make sure those heating (and maybe plumbing) parts are very well insulated. If you seal around them that will take care of the air infiltration into and out of the home.

[chrisexv6]

Cool, I will do that. The plumbing stuff up there is all ABS, and it seems to be just the vent for the drain system. Dont think it needs to be insulated, but the holes where they come up should be (and some of them are, I went up once before and used foam and caulk to close some of them).

The ductwork is insulated on the inside, Im currently re-affixing the flex duct (using mastic to seal it, along with sealing all of the duct boots to the plenum and adding balancing dampers while Im at it).

Funny how the fairly simple and inexpensive projects get overlooked, yet they have the potential to provide the best return on investment.

-Chris