GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Economical way to insulate detached garage

PLIERS | Posted in General Questions on

I have a 2 car detached garage.  Garage use to have a storage area on second level but after some damage from old roof I had to take off second level flooring and redo roof.  I want to use the garage in winter as a workout space.  I live by New York City.  What is an economical way to insulate and finish walls.  I’m thinking fiberglass batts with osb wall covering.  What about roof, do I insulate it?  Should I install a ceiling and redo storage area floor?  Looking for most economical way, it’s detached doesn’t need to be pretty just functional.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Brian Pontolilo | | #1

    Hi Joe.

    This is a guess, because one would have to actually get bids from contractors or price materials (if it will be a DIY project) to know for sure, but my guess is that the most economical route would be fiberglass batts in the walls covered with drywall, and a drywall ceiling with blown in fiberglass or cellulose on the attic floor.

    That said, garages are tricky and you could do all of that and still not find it a comfortable space. Maybe minimal effort is fine if you just want to heat it up or cool it down to a reasonble temp for a once-a-day workout. Otherwise, air sealing the walls and ceiling will go a long way towards improving comfort and some other details that you'll need to consider are insualting the concrete perimeter stem wall and the floor.

    Then there's the big hole or two: the garage doors, which are typically thermally inefficient and leaky. If you won't be using the space for cars, you could frame in the door openings and add a door and maybe some windows for light.

    What's your plan for heating and cooling the garage?

  2. PLIERS | | #2

    Hi Brian, thanks for your help. I have a infrared heater for garages that is 4800/5600 watts. Just looking to be warm enough to workout for an hour in winter and leave. Last winter heater didn’t do much but I have 0 insulation. Not too concerned with heat in summer, I can open doors and use fans. I’m an amateur DIYer so forgive me for stupid questions but any reason to use drywall over osb if price is similar, mold resistant drywall Is a few dollars more a sheet. Also can osb used be on ceiling or is it too heavy. Finally I want to leave a space open for second floor in between rafters on both sides so I can just throw a ladder up there to get to storage. Will the small open space make a huge difference in heat loss?

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |