Garage ceiling insulation questions

[nexgen91]

Hi there, I am looking into getting my garage ceiling (or lack there of) insulated and dry walled. It's a basic two car attached garage (nothing fancy). My dilemma is if I should go with a flat ceiling, or a vaulted ceiling with the original joist exposed (I wouldn't be able to install a lift or anything, but I do mostly woodworking and minor maintenance in there shop anyway) a note here: there is a massive amount of space between the ceiling joist right now (they lay front to back looking into the main door) where I store my canoe, and other misc items (sheet goods, boxes of parts, etc) and although it would be nice to continue to store things (especially the canoe) between these joist, that alone would not persuade me to go one way or the other. Now if I go with a flat ceiling, my contractor will be framing between the joist in order to install drywall. As far as venting goes, I have soffit vents, but no ridge or gable vents on the garage, there is a ridge vent on the house, and a small access door from the garage ceiling/attic to the house attic (the only way to get access to the house attic) that I was thinking I can keep open after the install until I get a ridge vent installed (not sure if this would help/work). Opinions on this?

My laundry room is accessed through my garage (yes my wife hates it) which is the reason I got permission to proceed with this insulation project in the first place, this is mostly "to keep her warmer/cooler while she is on her way to/from the laundry room" I am not looking to keep the temps as well regulated as the rest of the house (I'm thinking high 50's/low 60's in the winter, high 70's/low 80's in the summer) just enough to be comfortable when working/walking through with a space heater in winter, portable ac in summer. I live in southeast PA if that helps.

Given the two options for the ceiling, would one be more effective than the other at doing this? If (like I am thinking) the vaulted ceiling is less efficient at keeping temps regulated would it be worth it in order to keep the extra overhead space? I am not up to taking on this project myself (I am done with drywall for the foreseeable future, and hanging it on a ceiling does not interest me at all Thank you all in advance.

 

[nexgen91]

One more question to go with this, the roof is nearing the end of its service life (inspector estimated a year or two left in it) should I bother putting in the ridge vent now, or ride it out until the roof replacement?

 

[bczygan]

Your mention of a lift makes me think you might like one. Would you?

Right now, when the roofing materials are reaching end of service life, and with the inside roof structure unfinished, is the time to consider any major improvements. So what ultimate uses would you make of this space, if you could?

In other words, you can do anything you want, and now is the time to do it.

How long have you been there and how long will you stay?

Budget?

Photos?

And welcome to GJ. Please put your location in your profile.

Bill

 

[DC73]

One option would be to spray closed cell foam on the underside of the roof deck. With this approach, you could seal the soffit vents and your garage would become an unvented space. You could then choose to put in a ceiling or not. One minor issue with this approach is that during the winter and without a ceiling, the warm air in the space will rise to the peak and the area will not seem as warm as it would with a lower ceiling. Shouldn't be bad though.

Another option is to build a cathedral ceiling with conventional insulation. This approach would need a vent channel just below the roof deck from the soffit vents to the ridge.

Putting in a ceiling with drywall would allow you to blow celluose into the attic space which is a pretty good bang for the buck insulation approach. Pretty easy DIY as the big box stores will loan you a blower with purchase of insulation.

Yes, if you put in a ceiling with insulation, leave the access door the house attic open until you get the chance to put in the ridge vent. Since you're headed for a roof replacement anyway, I see no reason you couldn't wait on the ridge vent until then since you have the access door to let air flow between the two spaces.

You can find more information on BuildingScience.com and GreenBuildingAdvisor.com. Search for "cathedral ceilings" and "unvented attics" on both sites. The GBA site has a Q&A forum where building science gurus hang out. They may have more specific recommendations for your climate zone.

Depending on if you are in climate zone 4 or 5, recommended insulation levels are R38 to R49. Since this is a garage, you don't necessarily need that much but if you ever plan to heat or cool the space, it would be a good idea.

Good luck,

DC

 

[nexgen91]

Your mention of a lift makes me think you might like one. Would you?

Right now, when the roofing materials are reaching end of service life, and with the inside roof structure unfinished, is the time to consider any major improvements. So what ultimate uses would you make of this space, if you could?

In other words, you can do anything you want, and now is the time to do it.

How long have you been there and how long will you stay?

Budget?

Photos?

And welcome to GJ. Please put your location in your profile.

Bill

Thank you for the reply bczygan,
Im not sure I would use the lift enough to justify the cost, but it is something to consider. I have been in the house about a year now, would love to stay another 20 or so, but due to my career I could move at some point. If I do stay for a while I plan on building a detached shop which may have a lift. Budget it somewhat limited right now (kids and stuff) so I cant go to crazy. I dont have any photos on me but can post some later. Thanks again.

 

[nexgen91]

Yes, if you put in a ceiling with insulation, leave the access door the house attic open until you get the chance to put in the ridge vent. Since you're headed for a roof replacement anyway, I see no reason you couldn't wait on the ridge vent until then since you have the access door to let air flow between the two spaces.

You can find more information on BuildingScience.com and GreenBuildingAdvisor.com. Search for "cathedral ceilings" and "unvented attics" on both sites. The GBA site has a Q&A forum where building science gurus hang out. They may have more specific recommendations for your climate zone.

Depending on if you are in climate zone 4 or 5, recommended insulation levels are R38 to R49. Since this is a garage, you don't necessarily need that much but if you ever plan to heat or cool the space, it would be a good idea.

Good luck,

DC

This is what I am leaning towards, because I want to keep as much heated/cooled air in as possible, and it just makes sense in my head that a smaller space (overhead) will require less energy to cool/heat. I dont know what R value the contractor is looking at (Im still waiting on an official estimate) he quoted me $2400 for framing, moving my electrical out of the way of the drywall, drywall with tape/mud (roughed in), and insulation (flat ceiling). Once I get the estimate (should be in the next couple days) I will try to report back and see if there is any advise. I did the math on doing it myself and it came to about $1200 so I figured $1200 for someone else to deal with all that (especially the drywall) was not to bad. I am trying to wrap up a bathroom renovation that is going on five weeks now (I work 12 hour shifts, so dont get anything done during my work week) so I am ready for a break. Thanks for the reply