Insulating small attic above garage

[garrett1812]

I have a new home with a 2.5 car garage I am looking to insulate. The garage is mostly under living area, except it extends about 6ft forward of the house, and there is a 6ft bumpout on the side of the house. The walls and ceiling connecting to living areas in the house are already insulated and drywalled. I will be adding R13 insulation and drywall to the remaining walls (wall with garage door and half car bumpout), and R6.6 to the garage door. My question lies now with the two small attics.

I am not planning to heat/cool the garage. Primary goal is to keep the bedrooms above from getting too cold over the winter. The secondary benefit of a warmer garage will enjoyed as well. I may occasionally use a heater in the garage over the winter.

What is the best way to insulate these small attics? Blown insulation or batts?

What R value would be your goal? (located in northwest Indiana)

The garage at the front of the house is connected to the porch. Does this change how anything should be done?

Vapor barrier should go toward the garage area?

What should I do about the walls inside the attics that share with the living areas?

Any other input?

Thanks!!

Sorry for the poor quality of the pics. I will replace as able.


Pics of house:

 

[garrett1812]

Side attic

Approx 6ft x 20ft

 

[garrett1812]

Front attic

Approx 6ft x 20ft

Open to porch cover (see picture with ductwork (bathroom exhaust))

 

[garrett1812]

I am mostly curious about where the attic covers the house walls. Should I insulate this and how?

 

[DC73]

It's a bit hard to follow from the description and photos but the bottom line is that you want a sufficient thermal envelope (a blanket so to speak) completely surrounding the living area of the home. If there are any walls in the attic or ceilings that are not insulated and share a common connection to the living space, those need to be insulated (and should have been insulated by the contractor).

Insulation batts are easy enough to install in walls or on attic floors. Fiberglass is cheap but you must install in such a way to prevent air movement through the fiberglass or it's not as effective of an insulation. Mineral wool is fire resistant, sound resistant and blocks air movement albeit at a higher cost than fiberglass. Cellulose is fairly cost effective and you can pick up bags of it at Lowe's or Home Depot and they will loan you the blowing machine (you'll need a helper). Spray foam is great but is generally the highest cost and requires careful selection of a contractor.

Visit BuildingScience.com and GreenBuildingAdvisor.com. Both sites are good sources of information and you'll find a chart or diagram giving recommended insulation levels for your climate area. GBA also has a Q&A forum where you can pose technical question. That would be a good place to ask about your proposed vapor barrier.

DC