new guy, old garage needs insulation

[nagant]

From iowa, thanks. My 1930's 16'x16' wood garage has a 3 foot top ridge in center so four sloping faces to center peak. Rafters are full 2x4"s and are spaced about 2 foot on center (varies quite a bit). No heat but use a propane heater when i work out there. And the eaves have a half inch or bigger gap above the walls. I have 30 16"x8'x2" Dow Tuff-R foil on both face's i got for free. Should i cut those to fit between rafters in 16" lifts and leave flush with rafters? Can i block the gaps as i wont heat this more the 4-6 hours a week max. Walls are the same spacing and will work on that next, not sure as the spacing is over 24"s in a lot of places. thanks

 

[karoc]

Welcome nagant, dang Iowa all I can think of is cold and snow. Having a garage with no insulation to just having minimum insulation is a big improvement. I have those very same sheets on my house and my garage and I feel that they do help out alot. Since your spacing of studs varies you can cut the sheets for a snug fit. Get chance post some pics

 

[Sawdust_]

Cut the sheets a quarter inch smaller than the stud bay and use spray foam cans to make them tight. The resulting assembly will be air tight too which is even better than just insulation.

 

[nadogail]

Cut the sheets a quarter inch smaller than the stud bay and use spray foam cans to make them tight. The resulting assembly will be air tight too which is even better than just insulation.

I agree, any insulation is better than no insulation.

 

[May Pop]

To keep heat, any and as much as possible, you must stop air infiltration. A cold draft will steal heat as fast as you add it.

 

[theoldwizard1]

I have 30 16"x8'x2" Dow Tuff-R foil on both face's i got for free. Should i cut those to fit between rafters in 16" lifts and leave flush with rafters? Can i block the gaps as i wont heat this more the 4-6 hours a week max.

Cut the sheets a quarter inch smaller than the stud bay and use spray foam cans to make them tight. The resulting assembly will be air tight too which is even better than just insulation.

Sawdust is right on ! Don't overthink this. Most of your heat loss is through the roof. An addition 2" of insulation (foam board ?) might actually be better than insulating the walls unless you have a lot of wind. I would try it one winter before tackling the walls.

 

[jonesg]

My garage is rather old, first order of business was a metal roof to stop water leaking in. $600.
I did the walls and ceiling with 1 inch pink extruded foam, single car garage, cost me $200 with some 1x2 wood slats on ceiling.
Rubber seal for bottom of the roll up door. 23k Kerosine heater.
I just cut a hole for a 6K btu A/C unit.
After decades of wrenching outdoors its a joy.

 

[cruzer75]

i have a 14x21x 8ft ceiling shop/garage. 2012 put a new roof on, it rotted away (studs and covering) becasue the PO had put foil covered fiberglass upgainst the roof.

I didn't do anything to the garage ceiling for a long time, then finally wanted to enjoy working in the winter or at night with heat. Concentrated on getting the ceiling insulated(not even 100% sheet rocked and probably won't) this past fall and getting my heater put back up. It worked great and i was able to heat the shop with a 30kbtu Reznor unit heater on propane while in it with little problems...
walls are still drafty and door and overhead are just wood single layer jobbies with no insulation.