Insulate ceiling of garage?

[xJoey Dubsx]

So I am using some rigid insulation I scored from a buddy. It is made for roofs coincidentally. I am wondering if I should use the extra I have from doing the walls, and do the ceiling as well? I have an older furnace in the garage, so I don't want to waste energy, but don't know if it would be overkill and worth the extra work. Also, I know it wouldn't look the best, but then again how it is now isn't pretty or anything..

Should I do it?

My garage build:
http://www.garagejournal.com/forum/showthread.php?t=241773

The ceiling:

 

[sands35]

If you have heat, and you live in Cleveland (I grew up near Chagrin Falls), then you need to worry about condensation in the winter.

It doesn't look like you have any venting in the garage roof? Ridge or soffit vents?

You will need to take care of venting first.

If you put up insulation that isn't thick enough, you can get condensation and not know it until the wood rots away.

That aside, ceilings first, then walls.

 

[xJoey Dubsx]

Walls are insulated. I was wanting to vent it anyway for heat during summer. Brother is a roofer so have all the abilities to do so.

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[WanderingSol07]

I have a two car attached with walls and ceiling dry-walled. Walls are not insulated, only one wall in common with house. No utilities in garage. I insulated the ceiling with 4" fiberglass and now my garage temp is much more moderate and does not drop below 32 ever.

 

[xJoey Dubsx]

Would running a cheap bathroom fan or two, along with a cheap vent or two be sufficent? I plan on having a ceiling fan installed too.

 

[cspcrx]

I have a 4 car attached. I insulated the exterior walls, doors and have blown in the attic. My garage, by code, has two side vents on one wall for the gas water heater. I installed a bathroom fan in the upper vent opening, blowing out. It is on a HF timer that runs for a few hours in the evening and then again in the morning to **** the hot air out. Seems to be working vary well. My garage never needs heat in the winter, than again Im in Phoenix. It holds the heat from the cars very well!! Almost to well during the summer and that's where the fan helps.

 

[joe_padavano]

I don't want to waste energy, but don't know if it would be overkill and worth the extra work.

Heat rises. Without insulation in the ceiling, what keeps that rising heat in the garage?

 

[xJoey Dubsx]

Shingles lol. But That's what's why I asked. Assumed I should.

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[sands35]

If you have a buddy who is a roofer, then why not put in vents and do it right?

The basics is soffit and ridge vents according to code, insulation baffles at the soffits and r-30 on the lower cord of the rafters. It looks like your garage is attached? Then you will need Type-X 5/8 on the common wall and on the ceiling. 24" truss spacing requires perpendicular drywall sheets.

 

[xJoey Dubsx]

I am thinking Soffit vents.... Is there anyway to close them during winter so I don't have heat loss or do they need to be kept open?

Garage is attached, but no access from one to the other, you need to walk out side to get to house.

 

[sands35]

If you are doing a "traditional" insulation job, then the underside of the roof deck is, ideally, the same temperature as ambient. This prevents ice dams in the winter. There is separation between the underside of the roof deck and the insulation. Foam trays are used to provide that spacing and air circulation.

 

[bc_stang]

In my opinion, insulated garage is worth every penny!!! I just added insulation and finished drywall in my 25x25 detached garage. It use to be too cold to work in winter and too warm in summers. After insulation went up i noticed it stays 9-10*C warmer in winter then outside temperature and so far i have noticed it stays 12-13*C cooler in hot days. Plus now my compressor can be turned on middle of night and you cant even hear it outside as long all the doors/windows are shut!! Did i go overboard on insulation? SURE! but it was all worth it. I remember past winter i would have a small old 4' baseboard heater on for 4 hours (temporary heater till i get ceiling unit installed) and it would retain all the heat for 18-22 hours depending on how careful i was with opening doors/windows.

 

[xJoey Dubsx]

Did you do the ceiling?

 

[bc_stang]

yes of course, imo dont even bother if you are not going to do all walls and ceiling....leaving ceiling un-insulated would be like leaving big garage doors open. Hell i even got insulated doors.Totally worth it.

btw, what are your intentions with the garage? If its gonna be just to store your cars,household items,mower,etc then leave it as is. But if you are planning to spend more then 2-3 hours/week in it working on stuff then bite the bullet and insulate it depending how cold it gets in your area. Warm/hot garage is easier to deal with then cold/frigid temperatures in winters

 

[xJoey Dubsx]

I plan on working on it quite a bit, so yeah I will do them.