No ventilation in west facing garage

[tsmceo]

New home owner (August 2024) in Denver metro area home was built in 1992 With a 20x20 attached 2 car garage which is unfinished and unventilated. Walls are 2x4 and ceiling joists are at 8’6" with 24" spacing. Roof is a 8/12 pitch. Garage door is a basic uninsulated metal roll up
As it’s west facing and have no ventilation it’s very hot unsure what winter will bring. Anyway I started to add r15 to the walls but stopped when I realized no ventilation. So to ensure I don’t cause more issues looking for some advice on should add. Ventilation or just insulate the walls and the door or??????
Thank you

 

[bad_idea]

I had a 14x20 attached garage on my last house. The garage door was insulated by the PO. Two sides of the garage were adjoined to the house, and insulated. I removed the sheetrock on the remaining side, insulated, and sheeted in plywood. I never did bother to insulate the ceiling. There was a scuttle in the ceiling about 2' off of the back wall. I made that into a hinged door with an eyebolt in the face. I then welded a hook to a pole to open and close the scuttle without the need for a ladder. Whenever I went out into the garage I would open the scuttle, open the roll up door, and place a fan in the door opening blowing into the garage. Worked great! You could feel a draft blowing into the attic through the scuttle. Would cool the garage and the attic down to ambient temperature in the heat of the summer.

I never had issues with excessive condensation in the garage. In those particularly damp parts of winter when the temperature is fluctuating a lot I would turn the fan on to blow air around the garage. Leave the fan running 24/7 on low. Moving air holds more moisture and prevents condensation.

 

[niget2002]

The insulation should help keep the insides from rising in temperature as fast. But if you don't have any way of pulling cooler air in, then it will eventually warm up. Insulating your garage door would make the best choice. The garage door is just a huge metal radiator that's taking the sun's heat and radiating it into the garage. Insulating the garage door would help keep the sun's heat from doing that.

I have the same issue and am looking at doing the same. I do have a window in my garage, but we don't leave it open (It's hard to get to).

I keep my garage door cracked during the day, but I work from home and I do it so our cat can go in/out of the garage for food.

 

[racecougar]

Assuming you want to close in and insulate the ceiling, you'll need to add vented soffits and preferably a ridge vent on the roof (yes, there are less satisfactory means like gable vents, roof vents, etc.).

Does the garage really have a roll up steel door, not a sectional? I'd be surprised that that would be used on an attached garage.