[Todd_zilla]

Hello to all,


I am preparing to have a bonus space added over my existing, attached 3 car garage. I live in Texas, where heat is more of an issue than cold. The bonus space will be attached to the upper floor of the main house (it will tie into one wall). The added space will be a game room and home theater. When designing and building from scratch, what would be the best approach for insulating and temperature control for this space to make it as efficient and comfortable as possible?


Some of the details:

The ceiling of the garage is about 5 feet lower than the floor of the second story floor of the house, so there will be some room to play with if necessary. I was thinking that adding an exhaust fan in the garage was an easy first step. Then spraying closed cell foam to the floor joists and subfloor of the bonus room would work well combined with an abundance of insulated batting underneath it. I had also considered a radiant barrier foil application under the insulated batting and above the garage ceiling. The garage is currently drywalled, but I am willing to tear everything out and start over to get this right. I'd either create a new hvac zone for this space or have it run on it's own unit.


Thoughts? Ideas? What about the side walls and ceiling of the bonus space?

 

[Johnsteph10]

I think the spray foam would be a good idea as long as you don't mind the additional cost...otherwise, regular insulation is fine, too. Bonus rooms over garages are typically very demanding to keep comfortable..throw in a HT...and you'll need some serious insulation.


I would definitely have it on its own system rather than added as a zone. Heating it shouldn't be much of a problem in Texas but you're probably looking at some serious BTUs to keep it comfortable in the summer. You could probably look at one of the larger ductless/minisplit systems.


Are you adding to the roofline with this? If so, you definitely want to make sure you attic space above the addtion/garage is incredibly well vented and with plenty of insulation.

 

[mntmst]

Make sure the electrical is up to the task. I would pull a subpanel to the room from the main and run ever thing from it vice just extending existing circuits. You can then isolate the lighting/motor breakers to one side and run the A/V stuff on the other. A attic/whole house fan is a good idea to dump the heat out in summer, even here in Oregon it get pretty hot in my HT above the garage with no AC running.

 

[Todd_zilla]

Hi guys,


The cost isn't the issue, I just want to get it right... Everything I've read tells me that closed cell foam is the only real way to go for air and vapor barrier. I think that, combined with some additional insulation beneath it, as well as a radiant barrier beneath that, should take care of the bonus space floor.


I've attached pics of the front of the house as well as the garage angle. Sorry, it's rainy and overcast today as the garage photo shows... The roof line will be fine and the attic will tie into the existing attic seamlessly.


The electric boxes are in the garage, so running additional circuits will be quite easy.


Any other thoughts/ideas regarding insulating this area... I would ideally like to have it completely isolated from the garage in terms of temperature...