Installing Garage Ceiling Insulation

[Corie]

My soon to be mother in law wants me to install insulation in the ceiling of the otherwise uninsulated garage. The garage is directly below a bedroom and den area and those rooms are extremely cold and hard to heatin the winter time. I will be installing a woodstove up there for heat, but she also has asked me to insulate, which makes good sense.

My experience with insulation is limited so I'm hoping one of you guys can tell me what is necessary. They have the insulation, but I'm wondering if a vapor barrier is necessary since the garge is essential open to the outside due to leaky old garage doors.

Thanks in advance!

Corie

 

[Harley]

Not an expert, but I think in the ceilings I've seen what's been referred to as "proper-vent" or "tru-vent"? (though that may be a local brand name). Its essentailly a 1/8" piece of pink or blue styrofoam. It attaches in between the studs, and makes an air channel between the insulation and the plywood (or whatever roofing material). I believe this largely done for moisture/condensation and air flow to the soffit vents. Easy to put up before you stary laying the insulation.

 

[Rhone]

I'd use fiberglass insulation because it's fire retardent. You need a vapor barrier, it always has to face the WARMER side. If insulating from the garage, the paper would be right against the floor of the den/bedrooms above and the fiberglass insulation below that. The reason I prefer fiberglass in this situation is because it's always fire retardent. The spray stuff its fire retardency breaks down over time. Hopefully Elk can jump in and tell you how thick the drywall has to be. There's a certain amount of time a fire in a garage needs to be restricted to before being able to burn its way into living areas. The garage ceiling needs more than 1/2" drywall for certain, it may require 3/4" or 1" drywall so fires can't as quickly go through it into the living area even if you don't park a car in the garage. Plus, the added thickness acts as a sound deadner.

What kind of insulation did they get?

 

[Corie]

I know it's faced, fiberglass, but I don't know what the R-value is. I'm working on finding out.

 

[elkimmeg]

Tell us the froor joist size and we can tell what is needed for insulation

Harley forget the pink baffel system, they work in attics where there is sofit and ridge ventalation this will be a closed system

You should consides no less than R19 which has been upgraded to R21 fits in a 2/6 joist cavity If you have 2/8 cavity you can use the R25 plastic wrap much less icthier to handle or the higher density R30 you still can use R-19 or R21 in that cavity Bleieve me you will notice a huge difference with R 19 or higher. Again wise advice explained the vaporbarrier goes to the heated of floor.

How to install If time and money constraints kick in then you want to also purchase aviation wire which is friction fit between joist and will hold the insulation up. If you are planning to tighten the garage and make it compliant then against all living space 5/8" firecode sheet rock provides the minium one hour p fire protection. If planning to strap the ceiling and attaching sheet rock strap it for now every other one. YOU WILL HAVE ENOUGH STRAPPing to hold the insulation in place and more room to pull it threw. After insulated finish off the missing strapping but snap all lines to keep the strapping straight to begin with 16" on center and make damn sure your
4' and 8' strapping position are just that. It will save you a lot od cussing later. as for one person installing the sheet rock on the ceiling Rent the sheet rock rig that cranks it up into place and screw it off. Worth every penny for that rental. Mighty heavy 5/8" holding overhead and trying to screw it off even with two guys.

 

[Roospike]

My soon to be mother in law wants me to install insulation in the ceiling of the otherwise uninsulated garage. The garage is directly below a bedroom and den area and those rooms are extremely cold and hard to heatin the winter time. I will be installing a woodstove up there for heat, but she also has asked me to insulate, which makes good sense.

My experience with insulation is limited so I'm hoping one of you guys can tell me what is necessary. They have the insulation, but I'm wondering if a vapor barrier is necessary since the garge is essential open to the outside due to leaky old garage doors.

Thanks in advance!

Corie

I think you might of answered your own question.

since the garge is essential open to the outside due to leaky old garage doors.

We had a house with the same set up and it was cold in the 3 bed rooms and 1 bath above the garage . Leaky garage doors was the answer . We went from wood doors to the insulated steel doors and of coarse the new weather striping at the bottom of the door and side door stripping . I'm here to tell you it made a world of difference . Not only was the garage warm now it took care of the 3 bedrooms and 1 bath above the garage . You might want to take care of the problem at hand <leaky old garage doors> then do the extra if needed .

 

[Harley]

Harley forget the pink baffel system, they work in attics where there is sofit and ridge ventalation this will be a closed system

Oooops, sorry... guess that shows you should not take construction advice from an accountant

 

[elkimmeg]

Spike is right to button up the garage doors as well. New bottom gasketing applied with plain roof nails then check the side stop weather stripping.. That floor should be insulated and fire protected

Your girlfriend is lucky to have a concerned future to help her mother