# Insulate Attic Space above garage..Yes or No ?



## TheDoc46 (Jan 22, 2012)

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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## Windows on Wash (Aug 30, 2011)

Totally depends on where the dominant source of heat is coming from. 

What does the roof consist of and what is the structure of the roof/attic like?

A thermostatically controlled fan in the garage might not be a terrible idea to move some ambient air through the space and strip off the heat.


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## TheDoc46 (Jan 22, 2012)

Windows on Wash said:


> Totally depends on where the dominant source of heat is coming from.
> 
> What does the roof consist of and what is the structure of the roof/attic like?
> 
> A thermostatically controlled fan in the garage might not be a terrible idea to move some ambient air through the space and strip off the heat.


Hi my house has dark roof tile (again not the ideal color!!) but not something easy to change.. Garage walls are stucco block, attic is just rafters, with the sheet-rock attached with a knockdown texture to make the ceiling. plywood sheets separate the main insulated living area to the attic space. 

It does get hot in there. Its where I store all my empty boxes, hurricane shutters and tools that do not get a lot of use. Spraying it with a blow in insulation would be a pain, as i do have a lot of stuff up there, that i have to get to when i need it. I should also mention the attic space is well vented through vents in the roof and soffits all around.

Here's a pic of the house to make more sense.


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## Windows on Wash (Aug 30, 2011)

Gotta know the attic temps to be honest and where the heat is coming from. 

Some radiant barrier in the attic would help slow that transfer of energy and keep the attic temps down.


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## TheDoc46 (Jan 22, 2012)

I suspect a lot of the attic heat is coming thru the tile. You can't see the tile inside the attic. I can take a temp reading via a temp gun of the wood boards that make the roof up, (with tile and asphalt roof sheet sitting on top of the board) I wonder if that in itself acts as insulation.


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## Windows on Wash (Aug 30, 2011)

Either way, you will need to take some readings. Is the attic vented? 

Radiant barriers work well in climates such as yours.


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## TheDoc46 (Jan 22, 2012)

Windows on Wash said:


> Either way, you will need to take some readings. Is the attic vented?
> 
> Radiant barriers work well in climates such as yours.


yes attic is vented thru vents in the soffits. I'll get some temp readings, from the attic space and garage.


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## lenaitch (Feb 10, 2014)

TheDoc46 said:


> yes attic is vented thru vents in the soffits. I'll get some temp readings, from the attic space and garage.


Soffit vents are only half the equation. You also need roof/ridge/gable vents to allow the air drawn in through the soffits to escape.


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## Gary in WA (Mar 11, 2009)

Now that you insulated the doors, what else faces South/West... the roof. Insulate to stop the heat gain from there, also. Especially IF your HVAC is there... then insulate the walls as well. RB the rafters as said, and *no *fans, pp. 5, 6/67 here; http://www.floridabuilding.org/fbc/publications/AtticVentReportFinal.pdf

Gary


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## bondra76 (Apr 21, 2016)

curious what you come up with here - we have the same problem, except in Colorado

One note I have found - the brakes in your vehicles are scorching hot when you drive home from work, and that heat only makes your garage hotter. If you can avoid parking the car in your garage immediately (and leave it outside for an hour or so to cool off) you might save yourself 10 degrees.


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## AtticFoil.com (Aug 27, 2013)

You are on the right track. Since the garage is not a “conditioned” space, you are looking more for an umbrella effect compared to a jacket - so no regular insulation above garage. Here are a couple tricks to instantly improve the comfort in the garage. First, good start by insulating the door. Next, you want to cut a hole in the sheetrock in the ceiling on the opposite side of the garage door. Just between the ceiling joists work well. You can either leave the hole open, or get a air conditioned return grill to cover it an make it look nice. Then, adjust the proximity switch on the garage door and make it stop about 1/2” from the concrete. This will act as a big vent and allow air to come under the door and into the garage, out the top and then into the attic. If you put your hand in the hole, you will be amazed at how much hot air is leaving the garage. The next thing is to install a radiant barrier foil over the garage . The benefit of a radiant barrier is most noticeable over non-conditioned spaces (garages, sheds etc.) since it basically acts like shade. It will still be warm but not baking hot. If you do these things, the garage will be much cooler. Also, as mentioned above, letting your car cool off a little before parking inside helps too.


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## Nealtw (Jun 22, 2017)

AtticFoil.com said:


> Next, you want to cut a hole in the sheetrock in the ceiling


The sheet rock is there for 2 reasons, Slow a fire and protect the roof structure. Keep the auto off gasses from entering the attic.


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