Journal of Poor Homebuilding v.15 – VENT ALL THE GARAGES!

by Erik North on September 5, 2012

Post image for Journal of Poor Homebuilding v.15 – VENT ALL THE GARAGES!

Image from Allie Brosh at Hyperbole and A Half. She is wildly hilarious. Go read it.

This is another classic. I was going to write ‘Maine classic’ but really this found everywhere in new construction with attached garages.

I’ve written other posts about the challenges of insulating a finished room over a garage. These rooms are challenging to heat for a variety of reasons, the largest being that they’re dealing with unconditioned air on five sides. Compare with a corner bedroom which may only face unconditioned air on two sides.

This photo shows an all too common construction issue in many modern homes. This is the right hand side of the garage, photographed from the rear of the house. The builder installed continuously perforated soffits in the eave overhangs, venting the building. A huge, HUGE problem!

But why? Three reasons (at least in this house). First, the garage’s ceiling trusses run across the garage’s face, perpendicular to the soffits. That means any wind gusts, sea breezes, or hell, a sirocco will sweep through the soffit and through the fiberglass insulation in the garage ceiling. The trusses create 20 foot chutes for easy air flow.

Second issue…the garage ceiling trusses were directly attached to the main house’s framing. Plywood on top of the trusses, drywall underneath and a big hole in the middle. Normally, a pretty sizable problem…unless say, wind were blowing into the open soffits, across the trusses and directly into the house’s framing. That makes it a huge problem.

Third and this is just with this particular house’s layout, is the heating distribution. The house has forced hot water baseboard heat and the pipes were run through the garage ceiling. If you were to pull down the soffits, ten inches inside are the hot water pipes. Cold air is blowing across uninsulated and soon to be not so hot water pipes. No wonder the homeowner could never heat this room.

Ventilation when done properly can perform well in any climate. An improperly vented garage is equally flexible, performing badly in any climate.

Vented Garage


{ 2 comments… read them below or add one }

CK October 15, 2012 at 9:55 pm

please give the girl credit for her illustration…


Erik North October 15, 2012 at 10:40 pm

Good call…done.


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