Garage Ventilation

[Larry Frank]

I have a three bay garage with garage doors on each. The garage is attached but not heated or cooled. The walls and ceiling are studs and just roof trusses.

The problem is that the garage area gets very hot in the summer. The roof has no ventilation at all. I have noticed that very few garages in my area have roof ventilation. Is there some reason for this? The eaves of the garage do have ventilation in them but there is no place for the hot air to go up and out.

I would like to add ventilation to the garage. I guess that that there are a couple of possibilities. One would be to put ventilation on the end gable of the garage and the other is roof ventilation. My house has solar powered roof ventilators and the work well or I could just add the cheaper aluminum roof ventilators.

What have other people done and does your garage roof have ventilation?

[Brian Tymchak]

I have a three bay garage with garage doors on each. The garage is attached but not heated or cooled. The walls and ceiling are studs and just roof trusses.

The problem is that the garage area gets very hot in the summer. The roof has no ventilation at all. I have noticed that very few garages in my area have roof ventilation. Is there some reason for this? The eaves of the garage do have ventilation in them but there is no place for the hot air to go up and out.

I would like to add ventilation to the garage. I guess that that there are a couple of possibilities. One would be to put ventilation on the end gable of the garage and the other is roof ventilation. My house has solar powered roof ventilators and the work well or I could just add the cheaper aluminum roof ventilators.

What have other people done and does your garage roof have ventilation?

My garage attaches to the main house right at the ridge, so I have 5 or 6 of the standard passive-flow metal roof vents, and it doesn't do as good a job as I would like. I had the house converted over to ridge venting when I had the roof redone 4 years ago. It does a better job in my opinion.

Since you have soffit vents already, do you have a ridge where you could just simply add a ridge vent?

[glenn bradley]

My gable fan was inexpensive and lowers the temperature significantly. Depending on your roof elevation, you could use multiple fans. My roof line faces the street and for look's sake I went with one 1365CFM fan but, would have liked two. As it is the fan theoretically moves the volume of the shop several times an hour. Another negative for me is that the gable fan position faces into the wind. I am sure I would get a lot more out of it if I could run one inbound on that wall and another outbound on the opposite wall. Unfortunately the opposite wall faces into the house-attic.

[Myk Rian]

I have 3 roof vents in my 2 car garage. The roof is insulated, as are the walls, and I have a "Tornado" box fan in the center vent. It turns on at 95º. With the door open, the shop stays at outside temp. A couple small fans keep air moving. The door faces south, so I can keep it a bit cooler with the door closed. I prefer it open.
For the winter, I have a Dayton electric hanging on a center joist. Does a great job. I stuff insulation in the vents when it gets cold out.
With a 4 car garage, 4 or 5 vents will be needed.

[Lee Schierer]

Shame on your contractor, that is poor quality construction.

Roof vents will not only make the garage cooler, but will prolong the life of the roof. When we lived in South Carolina I installed the wind turbine roof vents and they did a terrific job of ventilation and didn't let in any rain even in torrential down pours. Unless you can pt vents in both gable ends, consider a full length ridge vent.

[Thomas Canfield]

It seems that most of the attention is being given to attic venting above the garage. You may want to consider adding a ceiling vent to the attic to take some of the heat out of the garage itself. I find that pulling down the attic stairs in my garage helps but then my attic has gable vents along with wind turbines. I will be changing to ridge vents when the roof is replaced due to hail damage in the future.

[Jim Matthews]

The ridge vent installed in my house was inexpensive and the most effective part of the replaced roof.

Unless you can draw colder air from somewhere below the slab, you'll be moving ambient air through the doors.
I've found that placing an open cooler of ice in front of a box fan cools a plume about three feet in front of the cooler.

Stand on the "downwind" side of the cooler for some relief.

[Gordon Eyre]

I have done several things to keep my garage a bit cooler. First I insulated the attic above the garage, second I put insulation on each of the doors, third I use a large fan just outside of the side door to blow the cooler morning air into the garage and out an open window. I shut this fan off and close the door and window as soon as it begins to heat up outside. This works pretty well for much of the summer unless it does not cool down all that much at night. Because I live in a hot dry climate I have even tried a swamp cooler but found that it pumps way too much moisture into my shop and was giving me a rust problem for my tools. I bagged that out quickly. I have to contend with over 100 degrees temperature for most of the summer so this is a real problem for me.

[Kevin Bourque]

Gable vents are problematic. Blowing rain and snow can easily get through them and cause problems. Most builders around here won't even install them anymore because of all the call backs.

[Alan Lightstone]

I had solar vents installed over the garage. Cost nothing in electricity and have been quite effective. Mine's insulated as well, plus have A/C and heating in the garage I use for a workshop. All-in-all makes it a very usable space. But I started with the solar attic vents.

[Rick Potter]

Great advice so far Larry, I have turbine vents on mine, and they seem to work well. The next step that really helped me was insulation on the ceiling and walls, as well as having no direct sunlight on any windows. I have an insulated garage door with windows in my shop which gets direct sunshine all afternoon. I put some of that 1" foam board on the inside of the windows, and it made a noticeable difference. Pops off in the winter.

Rick Potter