Insulating garage attic space ?


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Old 02-16-17, 11:41 AM
T
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Insulating garage attic space ?

I have a question for you guys.

My garage is south facing, and cos i live in the Sunshine state, the sun shines on those dark brown doors all day long. (HOA won't allow me to change the color of my garage doors) The heat build up in my garage was almost unbearable.

So i recently insulated the garage doors to great success. With a temp gun, i was able to measure 120f off the non-insulated panel, and 87f off the insulated. so i know its going to make a big difference in overall temps inside my garage. But even with the garage doors insulated, its still Florida and hot outside !

My home (that was built in 2009) has attic space above the said garage that's insulated from the main living area, so the area above the garage itself is not insulated. My question mark is, heat rises correct.... So if i insulate my rafters in the attic above my garage, will i not be trapping the heat in? and making matters worse by keeping the garage warmer than i want it? i could understand if i lived up north and didn't want to lose heat, but i want to lose as much heat as possible.. Being i've insulated the garage doors where a lot of the heat was coming in from, am i just not better off leaving it un-insulated up in the attic in the hope that heat escapes?


 
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Old 02-16-17, 12:54 PM
T
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I live in Connecticut so consider my opinion worth no more than the cost. It seems to me that by your logic you shouldn't insulate above your living space either. My suggestion is to insulate and provide ventilation (in and out) as you otherwise would in the living space. Also consider including a radiant barrier.
 
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Old 02-16-17, 04:25 PM
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My garages are fully insulated. Worst is pulling in a couple hot vehicles and then closing the door. It's like burying some hot rocks with a pig to cook for a luau. I can't say it's much worse since I insulated though. Ventilation helps a lot. Installing a air inlet somewhere low in your garage wall and another in the ceiling to let the hot air get up into the attic works well. The big negative is if you ever have a fire. Code requires your attached garage to be fully sheetrocked for a reason. If you provide an air vent up into the attic it's also a perfect chimney for a fire.
 
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Old 02-17-17, 02:44 AM
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I used to live in fla and know the heat/humidity too well While I don't think insulation will hurt any, making sure the attic has good ventilation will help the most.

More than likely your common wall with the house [including in the attic] has firerock [5/8" drywall] From the pics it looks like your garage ceiling is 1/2" drywall. Does your garage attic have separate attic access from the house?
 
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Old 02-17-17, 03:20 AM
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Tell us what that garage attic has for ventilation?
In hot climates there can be benefits to adding a radiant surface (as Tony suggested) to the bottom of the roof, between the rafters. Depending upon what you have for ventilation it could go across the bottom of those rafters. RB's work both ways, to reflect heat and to not transmit heat, thus preventing that solar energy from reaching the inside of the attic. More when you return.

Bud
 
 

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