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Oct 30, 2013, 03:27 PM
Our attached garage is located directly under our kitchen and dining room. The garage ceiling and interior wall (against the basement), is insulated with rolled insulation,plywood, and drywall. We'd like to insulate the outside garage walls, but in our area, if we install sheetrock, the space is then taxed as it becomes additional 'living area'. If we attach styrofoam sheeting to the concrete walls, would this insulate enough to make a difference?

Do you have any other suggestions that would help insulate, but not raise our taxes?

Oct 30, 2013, 04:02 PM
if the code specifically says "sheetrock," use slatwall. it has to be solid and caulked to prevent exhaust infiltration into the house.

the gotcha is there also should be a fireblock of at least 5/8 drywall between the garage and any attachment to the house.

I'd build a 2x4 wall, tied top and bottom tight to the existing material, insulate between there and the concrete of the excavation, moisture barrier, and then top coat of whateverboard.

sig: if this is a new economy, how come they still want my old-fashioned money?
Oct 30, 2013, 04:21 PM
I think I would question that with the authorities. Many garages are sheetrock to make them more presentable and of course insulated. That does not mean they are living spaces. It takes more than insulation and drywall to qualify them as such. As an alternative you could frame them out and then use a plastic sheeting such as they use in carwashes for ease of cleaning. There are several different grades. They can be cleaned easily.
Oct 30, 2013, 05:13 PM
I agree with redoverfarm and also that sheetrock adds fire protection {proper thickness, of course} as long as the seems have a fire coat applied. One mud coat applied, that is. Big Grin

Popeye only reached for the Spinach can as a last resort...
Oct 30, 2013, 06:37 PM
As an attached garage, it already has drywall on the ceiling and common wall to the house - as noted in the OP.

I would double check the fine print on that drywall = living space thing too. Especially if there is ducted H/A in the main house and not in the garage.
But, to answer your original question: Foamboard would work and would add extra insulation to your walls. It's easy to install and not very expensive. The biggest downside is that it's not very durable to any impact damage. You could also check to see what other materials can be used without being classified as living space. Plywood, the already-mentioned slat-wall, OSB, exterior grade sheathing like T1-11 would all work fine as an interior wall surface for a garage.

Oct 30, 2013, 11:26 PM
And to be considered living space I would think it would have to be properly set up with outlets as required by building codes

They make it look so easy on tv, don't they
Oct 30, 2013, 11:28 PM
And egress windows as well. Missed the drywall part from the OP. My mistake. Red Face Silly of me to think that an inspector would not make sure that the common wall was rocked to begin with. Dah.
But then with rigid insulation while adding R value, you are also installing a fire hazard. Would not an inspector require the insulation covered. Some do around here, but I do not have a current IBC book handy.

This message has been edited. Last edited by: CommonwealthSparky,

Popeye only reached for the Spinach can as a last resort...
Apr 28, 2014, 12:31 PM
I wonder if spammers stuffed into wall cavities would eventually turn to insulation? Or would they just deteriorate and create an unpleasant odor?

Reported this "idealistic and creative" spammer.

Where do these characters come from anyway? Were they blown out of the dumps by tornadoes? Frown
Apr 28, 2014, 06:27 PM
International Residential Code section N1101.9 - Spammers as insulation - spammers are not acceptable as insulation material as they are too dense to record any positive R-value.

Apr 28, 2014, 06:56 PM
Perhaps because they're full of hot air and "BS"? Or on the other hand perhaps it's because of all the holes and empty space in their brains...??

Or more to the point, they possess no R factor of a different nature - no redeeming social value.

Good one, Jaybee - you've provided my laughs not just for today but the whole week. Smile Big Grin

This message has been edited. Last edited by: GardenSprite,