I have flat slab garage door that I want to insulate. I saw many videos online and they suggest using garage door insulation kits. However in all the videos I saw the garage doors has the groove that can hold/support the insulating sheet.

The problem I have is that my garage door is old flat/slab style which does not have groove that runs along the hinges horizontally.

Any suggestions on what I can use to insulate the door and how?enter image description here

  • Is the door a single wall or double wall of a double wall screws could hold the insulation. Spray insulation may also be an option, I have not used it on doors but have insulated metal buildings and it sticks to the metal quite well. – Ed Beal Nov 8 '19 at 14:49
  • Old style flat slab garage doors are carefully matched to their hinge and spring assemblies according to their weight. Acknowledging that insulation is generally not very heavy, you still need to be aware that any change could affect the safe opening and closing of the door. Be prepared to adjust the springs, and if you are not familiar with that you should get a professional to do it because it can be very dangerous. – Jimmy Fix-it Nov 8 '19 at 17:13
  • Thanks jimmy. Do you think gluing the foam bord will be problem. I terms of weight? I guess they won’t add up too much weight. And BTW when you say adjust spring and safe opening of the door. What exactly you meant for that? – Mayur Nov 8 '19 at 18:10
  • ED, the door is single panel old door. Even when I touch it right now it’s very cold. I don’t think spray foam is an option as far as cost goes. And on top of it how would I stop the foam getting into seam. – Mayur Nov 8 '19 at 18:13
  • Did you ever get this resolved? If so, please give a check-mark to the answer or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer. – FreeMan Aug 4 '20 at 12:48

I would use 1" or 2" rigid foam. You can glue it, but I would glue and use small bolts and fender washers on both sides of the door to keep the bolts from pulling through. #8 screws or carriage bolts should both work. Carriage bolts would look better. I would use locking nuts also. The foam's R-value is not as high as I would like.

Perhaps another alternative is spray foam--but I am unsure how that will work on the door seams.

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