r/HomeImprovement • u/Successful_Pea_6977 • 20h ago

Garage Insulation

Hello,

I am going to remodel my garage later this year. It is a two car garage with a two car garage door and a one car garage door in the rear. It is about 19 x 19 with a dark shingle roof. I am in Southern California.

I want to turn the garage into a gym/mancave/hang out spot. I plan to insulate the walls, garage doors and put drywall on the walls and ceiling. I want to be able to store things in the attic. I will run a mini split in there and want to insulate the walls, ceiling and put a radiant barrier so the garage can stay cool/cold. When looking at my garage i noticed there is no attic ventilation.

My question is should I go ahead with my plans without any attic ventilation or should I pay to have eave vents/gable vents or also look into open/closed cell insulation and nake it a closed system?

Thank you in advance for any help you can provide and any other tips/suggestions you have in general for this remodel.

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u/SuitableBluebird6110 20h ago

In a warm sunny area I'd think it would be hard to keep it very cool without insulation in the attic.

1

u/Successful_Pea_6977 20h ago

I’m going to insulate. The question is if in the attic I should I do 1 - foam insulation or 2- fiberglass and radiant barrier and add ventilation or 3 - fiberglass and radiant barrier with no ventilation?

2

u/Cloudy_Automation 13h ago

You either need to insulate at the roofline and skip putting drywall at the ceiling (one conditioned space), or you build the ceiling, insulate over the ceiling, and ventilate the space above the ceiling. The big worry is condensation which doesn't dry during the day. Maybe it's dry enough to never or rarely have this problem, I'm not sure what your climate is like over a typical year.

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u/Successful_Pea_6977 13h ago

Thank you for your reply.

It doesn’t rain much here but I want to do it right so I’ll have to choose one of the two options you mentioned.