Insulation for Detached Garage - Workshop & Office Space

[fourstringriot]

I inherited a 24x28 pole barn when we purchased our home. Over the past 2 years I've poured concrete in it and had stairs added to use the attic space above (7' at peak).

The goal of the detached garage is to make it a workshop/garage downstairs which will be heated occasionally (I am in WI, so it will be heated during the winter when I need to do work, but not ALL the time as I will be opening/closing doors quite a bit to store the truck and ranger) so the majority of the time it will be cold.

The upstairs will become my office, which will need to be heated (maintained around 55) and bumped up when I am in it and not on the road, as well as air conditioned in the summer. I wanted to get some general thoughts about my plan and if there's anything I should change:

1. The building will be close cell spray foamed. 2" on all exterior walls and 3" on the roof.
2. I was planning on adding R-19 batts in the ceiling joists below the office space (the entire ceiling of the garage). This would allow me to keep the office heated and maintained without losing heat through the floor if the lower portion is not heated.

3. I will have a BigMaxx or other propane heater for the downstairs portion
4. I will either have a split unit or another propane heater upstairs for heat and either the split unit or skylites for air circulation.

All that said, the two main questions I have are - since i'm doing the entire structure in spray foam, do I need to insulate the knee walls upstairs? And, if I don't insulate the knee walls is it safe to assume that the R19 batts in the ceiling below will effectively keep it a separate space?

And is there anything I should be doing for ventilation? All windows are currently fixed so the garage doors & skylights will be the only ventilation as planned.

 

[Cypherian]

Hey,

Based on when we converted the attic space above our kitchen in Maine I would say insulate the knee walls. The floor was insulated and as you might imagine it was heated when the season required. The cold radiated off the knee walls from the roof so we went back in and insulated them , thankfully we had put doors in so we could get behind them. The doors are inset 2 inches (2x6 wall studs) so we ran hard board insulation on the back of them and weather stripped the opening. The doors still were cold so we built a false panel with insulation on the back side toward the door and it pops into place with 4 barrel bolts. I am not up there to take a picture but you get the idea. See what others say but I imagine you will run into the same thing even with the foam on the underside of the roof.

Cypher

 

[CNGsaves]

Pictures tell a thousand words . . . . let's SEE what you've got !!

You've been on GJ a year and half so you've likely seen many times the advice to Update GJ Profile with a location as really does come in handy for other GJer's. See you're in Wisconsin so you'll need lots of insulation !!

 

[fourstringriot]

Here are a few pictures of current state.

 

[fourstringriot]

Hey,

Based on when we converted the attic space above our kitchen in Maine I would say insulate the knee walls. The floor was insulated and as you might imagine it was heated when the season required. The cold radiated off the knee walls from the roof so we went back in and insulated them , thankfully we had put doors in so we could get behind them. The doors are inset 2 inches (2x6 wall studs) so we ran hard board insulation on the back of them and weather stripped the opening. The doors still were cold so we built a false panel with insulation on the back side toward the door and it pops into place with 4 barrel bolts. I am not up there to take a picture but you get the idea. See what others say but I imagine you will run into the same thing even with the foam on the underside of the roof.

Cypher

Thanks - I really want "clean" walls upstairs so I dont think i will build access doors up there, however I do have access to behind the knee walls from the stairwell. I will keep that access as it makes great storage for seasonal things like my fishing gear.

 

[fourstringriot]

Any other thoughts on this? If I don't do rolled batts in the knee walls, i'm thinking of atleast attaching rigid foam to the backside of them?