Insulating a Houston garage
As you well know it is unbearably hot here in Houston a minimum of 7 months of the year.
About two years ago we moved into a prebuilt but new home with a 3 car attached garage.
The garage/house faces west and both the two bay garage door and single bay door are “factory insulated”. The construction of the walls is a rock/brick veneer /air gap / 1/2″ Dow Styrofoam Residential sheathing ( taped and flashed to form moisture barrier) stud cavity/ 5/8 gypsum painted with a latex paint which will be repainted sometime soon. The exterior walls as well as the area above the garage is un-insulated. The garage stays about 10 degrees cooler in the summer with the doors closed than the outside air temp.
The garage is about 650 sq. ft. with 10 ft ceilings
I would love to add a mini-split to this garage (I am thinking 18k BTU) in order to make this area bearable for my two sons to work in the evenings and on weekends.
Obviously insulation above the garage is easy to do and should be done. All I need to do in prep for that is add the baffles so the sofit vents aren’t covered.
It is the walls I am concerned about. I would love to blow or have cellulose blown into the walls. Since it is a garage I am fine with it being done from the inside. I am however concerned that the foam is the only sheathing and it’s ability to hold the pressure of dense packing cellulose in retrofit application.
Is the wall insulation something that can be done. Is it a necessity for this use application.
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