Building a Home Garages/Workshops Design Dilemma

Taking Edge off Heat in Closed Garage

5 years ago

In our planned build we'll have an attached side facing GA with a window facing front. In South and West, closed garages get VERY HOT. Short of anything more extreme like A/C looking for simpler solutions to take the edge off the heat that builds up in a closed GA in hot 100*F summer climates...

I've seen 'some' new homes in area incorporate some sort of small concrete grate in an exterior GA wall with wire mesh behind it. Doesn't exactly provide cross ventilation but it's something I suppose. I also suppose with the larger mesh - a good entry for pests like scorpions.
With the house having spray foam in attic - it will be closed off from attic over GA. But could still put fiberglass batting in the GA exterior wall and maybe foam sheets on the GA door.
Could introduce a vent(s) in the GA ceiling drywall and perhaps soffit vents in that section of the house if code allows. Could even put fan in the ceiling vent perhaps.
Could forego the windows in the top row of the metal GA doors to mitigate the Western sun getting into the GA.

Comments...

Featured Answer

David Cary

5 years ago

last modified: 5 years ago

So GA is Georgia of course and not really an accepted abbreviation for garage. I only make that point because I keep thinking you are in Georgia but there aren't scorpions in GA.

I have a West facing garage with no windows in NC. It is the rear of the house. I think the most obvious answer is design - don't have a garage up front where you feel like you should have windows. Yours is side facing so can you skip the windows?

Garage doors come with various R-levels. No foam sheets needed. I think I went with R-10 or so which was a $200 upgrade from the standard R-5 or so. I don't really remember the exact numbers.

I put some bats in the ceiling and walls but mostly that was to retain some heat in the winter but it probably helps some in the summer too. Ours is never that hot despite a west facing door - and some southern windows. But a 50 year old oak helps a lot.

How aggressive to be would need to include climate. AZ is not NC or GA. Trees are the really obvious answer but not always possible. A radiant barrier on the attic sheathing is cheap and easy. EVs help some. Overall, insulation is a mixed bag - prevents night time cool down even while preventing day time heat. Focus on reducing solar load - which you probably do anyway if scorpions are an issue.

I always like to point out that foaming an attic is not usually money well spent but it does depend on a lot of factors. My house has a negative HERS rating with fiberglass on the attic floor. (Negative because of solar - it is 50 or so without).

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Comments (10)

PRO
Patricia Colwell Consulting
5 years ago
IMO insualtion not only keeps the cold out but the heat too and use solar shades on the windows to help control heat and then places for the heat to escape of course like soffitt vents . I guess better construction all around.
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Anna (6B/7A in MD)
5 years ago
last modified: 5 years ago
Thanks, David! I kept thinking he was talking about Georgia.

We added a garage with attic last year and installed insulated siding and garage door, the attic is insulated with a ridge vent. We have brutally hot summers here and the highest temperature we’ve had was 85 degrees and the lowest was 50 inside the garage.
PRO
beesneeds
5 years ago
Put in a couple barn roof vents in cupolas. Mechanical ones work just on heat rising, but there are motorized ones too to draw the air up and out.
res2architect
5 years ago
last modified: 5 years ago
If the rafters are foamed the attic is probably sealed instead of vented in which case you shouldn't disturb it. Adding insulation to the walls will help the most. If the walls are exposed to strong sunlight a radiant barrier might also help.
chispa
5 years ago
last modified: 5 years ago
As far as those wire mesh opening for ventilation, I have them in my older garage in California, but would not want them in most other states that have way more bugs. Newer garage in back does not have them. We don't even have screens on the french doors and only get a fly in the house once in a while.

I don't think you will be able to insulate GA ... Georgia! ;-)
PRO
Mark Bischak, Architect
5 years ago
I am glad I am not the only one confused by the garage facing Georgia. My garage faces Canada.
JP Haus
5 years ago
There may or may not be scorpions in Georgia, but there are in other southern states, especially when you live on a rocky ridge. None have gotten into our garage through the vent screens, but they do manage to squeeze in any place the weather stripping has gotten compressed. I've also found several desiccated scorpions in ceiling light fixtures and in the attics, as well as live ones in the bathrooms.

As for garage venting, there used to be a small business that sold vents and fans for installation in garage doors that connected to the door opener. You could set a timer for them to run X minutes after each door opening or when the temperature reached a set point. We had them on a previous house and in one garage of a current house, and they do make a big difference. Unfortunately, sole proprietor closed down several years ago. We're looking at options for our new house.

Here are some links that might help:

https://basc.pnnl.gov/resource-guides/mechanical-ventilation-attached-garage#edit-group-scope

https://www.rewci.com/garage-ventilation.html

https://www.rewci.com/panasonic-whisper-wall-fan-fv08wq1.html

https://www.aircycler.com/pages/garagevent

https://www.tamtech.com/product-category/ventilation-fans/garage-fans/
User
5 years ago
Are electric exhaust fans legal in your situation....e.g., no gas appliances.
David Cary
5 years ago
Ok - I don't think of scorpions in GA but maybe there are. I think of them in the desert southwest but I am no expert....