Garage ceiling insulation

[Kid]

I 'm not sure if this is an appropriate forum for this, but I'm sure someone out there can give me an opinion.

I own a raised ranch. The three bedrooms are over a finished garage. (The house is 30 years old and I assume that there must be insulation between the bedrooms and the garage ceiling drywall.) However, when it gets cold (Chicago) one bedroom floor is always colder than the rest. (Maybe because it's the NW corner of the house?) It's carpeted/padded same as the other rooms.

Any problems if I install some foam board to the drywall on the garage ceiling? Do you think it would help? What's the best way to install it?

Thanks all.

[pushkins]

There are a few problems your going to face.
1. Foam is going to give you around a max of 3.3 - 4.5 R / inch so you might get R8-R9 value.
2. The foam will deteriorate rapidly unless it is covered, so gluing to to your existing drywall will be a very temporary measure.

The biggest issue is going to be code violation. Code doesn't allow foam insulation to be left uncovered in a garage, ESPECIALLY with living space above (your bedrooms).
You could however glue the foam insulation to the drywall and then apply a second layer of drywall over the top to encapsulate it. Min. thickness of drywall in a garage with attached living space is 5/8".

Were it me, I'd pull down the existing drywall in a small section, look to see what R value insulation is in place. If it is less than R19 then I'd be looking at replacing the insulation with R19 and re drywalling the ceiling.

Another option would be to look at the insulation in the walls of the garage.

[Kid]

Thank you very much for the info. The possible code violation is good enough reason not to do it that way.

It's a typical track development in a incorporated community. I can't imagine that the builder put less than an R19 in there. It's just kinda weird that it affects one room more than the one directly next to it. Both rooms face west, but the one with the colder floor is on the northwest corner.

I guess one of these days when I feel energetic I'll cut down a section and see what's up there. I'll put this on the "possible project" list.

Thanks again.

[Hube]

It may be the insulation is quite adequate .
Are there any "return " air grilles in these rooms? Return air will allow cold air to get back to the furnace. Return air also allows a room to get more supply (heat) into it.

[Kid]

No Hube. There are no returns in these rooms. I've had the same thoughts as you regarding the insulation. It might just be the way it is. There is only one window (west side). I am going to have new siding put on the house and I'll be certain to take whatever steps I can to make the house more energy efficient.

Thank you for your thoughts.