Garage insulation

[cmbicycles]

I am teaching from home in my garage for the foreseeable future and I need to insulate it to take the edge off when it gets cold, and keep the heat in when I run a heater. I had planned to upgrade the electric and insulate down the road to make a year round workshop. Need to do that sooner now. It's just served by a 20a circuit, so planning to add some more capacity now as well. You can see all the electric is flexible metal conduit, so could just leave that exposed on top of the walls as well, since it's just a workshop.

It's a 16x24 detached garage, 2x4 walls and 2x6 roof, everything 24"oc. I plan to insulate and drywall the side walls and replace the garage door, but am torn on the upper end. We use the rafters for storage so I'd need to either sister some ceiling rafters and make a door to get the thule box up, or install baffles between each roof joist and insulate the roof. I'm leaning towards doing the roof, laying baffles from the soffit to the ridge vent to leave room for air flow, and just leaving the vapor barrier exposed.

Anyone done this? Am I crazy to consider it? I'm thinking I'll leave the roof insulation uncovered as drywall would be a pain up thru the rafters. Other options or advice welcome.

Picture of the bike corner attached.

[Louis]

These folks had a "room above the garage," but perhaps it isn't that different from your situation, if you're going to heat the garage:

https://renosemipros.com/insulating-...er-the-garage/

[el cheapo]

In my state if you make improvements where additional heated/ac space is added it will increase your property taxes if the tax office finds out.

[fogrider]

Originally Posted by el cheapo

In my state if you make improvements where additional heated/ac space is added it will increase your property taxes if the tax office finds out.

how would the tax office find out?

[dgauthier]

The smartest advice I have heard for do-it-yourself refinishing of a garage is to call your local building inspector out. They can tell you what approaches make sense and are up to code.

[Davist]

Originally Posted by fogrider

how would the tax office find out?

you should pull permits in general.. we had someone do something next door, and got a tax bill for a shed (we had already lived here 10 years and it was there when we moved in) that we had to dispute.

[Tandem Rider]

Go see the building inspector first, not second. S/he will be able to give you a lot of advise on what you are trying to do. The LAST thing you want is to be enemies with the inspector. They can and will make you de-construct to allow for inspection. They will tell you what permits are required and what inspections are required and at what stage each inspection is required. As far as what you need for electrical, heating, A/C, structural, etc a permit allows you to work with the utility company and a contractor. No utility and very few contractors will touch an un-permitted job.

That being said, since you are going use the space for more than storage, you probably will have to cover the insulation with sheetrock, both for fire code and to protect your lungs from fiberglass. The side benefit is you may be able to wire the shop with romex wire since you are putting up sheetrock.

Sounds like a great space with lots of uses, have fun with the build out!

[batman1425]

Another datapoint - you may want to bring in a structural engineer to take a look at your roof construction. Many garage roof structures are really only designed to support the live and dead load of the roof itself and keep the walls of the garage from bowing outward. Lots of variables factor into this but the chords (2x6 in your case) may not support much additional weight safely. Even drywall and blown cellulose can add up quickly in the weight department. An engineer should be able to give you a lb/sqft recommendation.

Some don't realize this and pack the ceiling full or close them up not paying attention to how much weight they are adding with the finishing materials. That can lead to sagging ceilings and in a worst case, collapse if you're not careful.

Once you've got an idea of what the chords will support, you can figure out what makes sense from a function, performance, and aesthetic perspective - drywall and lightweight insulation, spray foam on the underside of the roof deck, etc. If the chords will handle it, you could finish it out and make provisions for a storage space with pull down stair access.

In your climate, think about vapor barrier too. Lots of contentious information out there, but if you will be heating the space, think about where condensation is likely to form and how to control it.

[adampaiva]

Wow you guys love to make a project more expensive. He doesn’t seem to be creating a new bedroom or anything. I’d personally not bother with all of this inspector/permits stuff if this was mine.

Why will Sheetrock be particularly difficult on the roof underside? Doing it yourself or hiring that out? You could pop in rigid foam insulation to the underside and choose to cover or not? Not sure if there are sufficiently fire retardant options to leave exposed. Or add nailer strips and just sheetrock between the roof 2x6’s.

[lzuk]

Easiest insulated ceiling might be rigid foam on top of the ceiling joists. If you go with drywall you should fir the undersides of the joist at 16” center. Shouldn’t need a permit unless you add electrical and or plumbing as it would still be a garage and not living space

[Dave]

Building inspectors are not your personal construction consultant. They only come out after permits are granted and you've reached a stage of construction that requires an inspection. For example, if the wiring is modified, it must be inspected before drywall is applied.

It's not hard to find info about the acceptable span for 2x6 ceiling joists, assuming that drywall is applied. The weight per square foot is really small, under 2 lbs per square foot.

I the ceiling is to be dry walled, then the electrical wires can generally be moved to the side of the joists and flexible conduit is not required, but there are areas where codes are more strict than NEC requires.

[batman1425]

Originally Posted by Dave

Building inspectors are not your personal construction consultant. They only come out after permits are granted and you've reached a stage of construction that requires an inspection. For example, if the wiring is modified, it must be inspected before drywall is applied.

It's not hard to find info about the acceptable span for 2x6 ceiling joists, assuming that drywall is applied. The weight per square foot is really small, under 2 lbs per square foot.

I the ceiling is to be dry walled, then the electrical wires can generally be moved to the side of the joists and flexible conduit is not required, but there are areas where codes are more strict than NEC requires.

OP says 16x24 footprint with 2x6 ceiling joists 24”OC. Assuming the joists span the 16’ there’s probably not a lot of dead load wiggle room there. Probably enough for drywall and insulation, but that’s it. I wouldn’t use it for storage and that. If it was me I’d have an engineer look at it just to confirm the load limits before putting rock up but yvmv


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[Dave]

A brief search yields some relevant info.

https://www.mycarpentry.com/joist-span-tables.html

[HenryA]

Spray foam the whole thing?

https://www.greenbuildingadvisor.com...oam-insulation

Your structure may or may not be suitable. Best part about it is its over and done in a day when you hire it done.

As to the need for permits, etc. Read your county/city regulations and find out. Every place is different. Everywhere from no permit needed to extensive architect and engineer stamped plans and strict inspections. The only rules that matter are the rules where you live.

[robt57]

Get batting of correct width with vapor barrier one and staple it to the roof rafters. Vapor barrier facing down. I'd get 2x6 even though you really should have some air under the sheathing. But 2x6 in 2x6 rafters spaces will sink a little in time and leave a little air space to the wood in time.

Your real issue IMO will be the concrete sucking the heat outta your feet. Decide on a corner for your desk and put a few 3/4" horse mats down over the cement there, and a small heat pad made for under a desk for your feet while you sit.

Make sure the weather stripping on exterior doors is good/new/tight, insulate the garage door panels if only thin Aluminum one sided.

Get a third horse mat for your bike trainer area...