Questions on insulating garage ceiling?

[Motorman55]

What's the best way to go as far as insulating the ceiling of my attached single car garage? The walls were previously insulated, but there's none above the ceiling.

I took a couple pics. Access is fairly good.

I'm thinking of the rolled fiberglass but not sure which type and R-Rating to use. Do I need the paper backed type or non-backed type? I may have to slide it under the plywood area that the central A/C unit sits on thats located at the rear of the garage. I need to get my inspection camera out to see if that was left uninsulated too.

There's wiring running across the ceiling. Can I lay the insulation on top or do I have to re-route it.

The garage gets like an oven in the summer as the sun stay on the long side of the garage. There's a standard window located on that wall near the overhead garage door. I have a new 5,000 BTU window AC unit that I want to use there.

Thanks for info...

 

[spudley]

From those pics it looks like you could blow in cellulose. Easy and cheap.

 

[The Cobbler]

are the soffits vented? you need to dam them so as not to close off the ventilation. use as much insulation ie r40 if you plan on heating it.
I would price blown in fiberglass, it might surprise you how competitive it might be. I had mine done for less than I could buy the batts for .

 

[Motorman55]

From those pics it looks like you could blow in cellulose. Easy and cheap.

Its all open from the front of the garage to the back side where the A/C unit sits and where we have a lot of stuff stored. Lot of work to remove that stuff and cover the A/C unit, etc. Guess I could go that route depending on cost.

 

[Motorman55]

are the soffits vented? you need to dam them so as not to close off the ventilation. use as much insulation ie r40 if you plan on heating it.
I would price blown in fiberglass, it might surprise you how competitive it might be. I had mine done for less than I could buy the batts for .

Only vent I see is the one Gable vent on the garage side. Air is vented by a roof fan at the far end of the house.

 

[The Cobbler]

you might want to look at more venting while you're doing it

 

[rburke65]

You need to add vents in the soffits and then blow in cellulose or Fiberglas

 

[Motorman55]

As you can see by this pic, the rest of the house is open to the garage area. Lots of the Central A/C ducting runs down across the other rooms. I think there's another Gable vent at the far end. Lots of insulation on that side.

I guess it was original closed off from the garage area when the house was originally built. It had wall A/C units previously. Looks like some of the sheetrock separating the garage from the main house was cut out for ducting. Not sure if this is ok or not.

 

[The Cobbler]

that may have compromised the fire rating for the garage . you can close your eyes to it, or dig deeper and see if you have to do anything to get the proper firerating back.

 

[Motorman55]

I'll look into that. I can access it if I need to re-sheetrock that area. Thanks.

 

[The Cobbler]

I'll look into that. I can access it if I need to re-sheetrock that area. Thanks.

might need a fire damper on that flex duct too.

 

[Motorman55]

The A/C unit was originally over the living room. Condensation from the unit filled the overflow pan and it damaged the ceiling.

The previous owners, my FIL/MIL had the A/C company move the unit over the garage. Hence the cutting of the sheetrock between the garage side and the living side and the ducting running through.

I can see that they cut out the sheetrock to access. Looks like I'll have to see what needs to be corrected. Yet another thing to correct. Thanks.