Source
r/HomeImprovement•
iaremonkey

Is my attic ventilation all wrong?

My gable fan is currently dying in my attic and I was looking at what I had in the attic and from reading I've been doing it seems my attic ventilation is all wrong. I currently have 2 gable vents on the North and South sides of the house and a ridge vent on the roof. I imagine the gable vents are original to the house and the ridge vent looks like it was added when the roof was last replaced. I currently have no soffit venting and the insulation runs up over top of the current wooden soffit. Also none of my bathroom exhaust vents are vented outside, which seems like with the gable fan, conditioned air might be getting sucked out of them.

My house also has a retrofitted central air system up there with insulated duct work and it's struggling a lot during the afternoons to keep the house cool and I think that the venting is part of the problem.

I think I didn't notice this problem before I believe because the roof was shaded by a large maple tree that blew down last fall and the attic was kept cool because most of the sun was blocked from the roof during the day. Before that tree came down, the gable fan rarely turned on.

What's the best path forward? Should I remove the gable fan, add soffit vents and vent the bathroom exhaust vents outside? Should I replace the gable fan? Who should I call to do this kind of work?

Posted Jul 22, 2020, 2:14 PM UTC

14
ailee43•

if you have gable vents and a roof vent what you want is the roof vent to the be the exhaust, and both gables to be the intakes. The fans if you have enough square inches of roof vent and gable are not necessary and may hurt.

The ideal solution is what you proposed. Soffit vents and ridge vent, but gables can work if sized right

3
limitless__Advisor of the Year 2019•

You are right that ventilation setup will not work optimally. It's ridge+ soffit or gables. Not a combination. Goes without saying that not venting the bathroom vents is a really bad idea.

No matter what you will need to fix the bathroom venting situation. I would call a roofer and ask who would do that work.

As for your gable/soffit/ridge. Tough call. Two gables plus a ridge vent will still work OK just not great. Ideally you would put soffits in and close up the gables but that seems like a lot of work just to slightly decrease the temperature of an area that's unconditioned anyway. I think it would boil down to price for me and how hot the attic is now. It should not be too bad since gable vents do work.

2
bluespearmen•

A vented ridge solves 80% of the attic venting but the calculation for having the right amount of venting is total square foot of the space say 1000sqft should have 32sqft of venting openings . 1/300. Hotter places have different equations . Talk to a sprayfoam contractor about an insulation upgrade. And put some proper soffit in .

2
idlefoot•

I would look at how much and the type of insulation in the attic as well as venting any exhaust fans outside. Vent fans venting in your attic can cause mold to form on the roof decking and rafters. Those you can do yourself fairly easy, just use a damper that is usually used for dryers and buy some of the hard piping and elbows. If you have fiberglass insulation you can see an air infiltration by pulling up pieces and looking for discolored sections. Air movement will be somewhat filtered by this.

2