How To Insulate a Garage Door

One of the most common questions is weather or not to insulate a non-insulated garage door.

Many new homes are built with non-insulated garage doors. This is usually because its less of a cost to the home builder and/or the home owner. Non-insulated garage doors are inexpensive but there are a couple of reasons why they are not ideal. First, for obvious reasons, the non-insulated doors are going to let a lot of heat out, and let the cold in. Secondly, the non-insulated garage doors are very flimsy, making it easier for components such as hinges to flex and eventually break. Lastly, insulated garage doors don’t dent quite as easy on the outside as non-insulated doors.

A Few Things To Consider Before Insulating a Garage Door

  1. How much R-value do I want?
  2. Will the insulation add extra weight? and if so, what will happen?
  3. How much do I want to spend?
  4. Can I just replace the garage door panels?

1. How much R-value do I want the garage door to have?

Most manufacturers will offer two types of insulated garage doors. The cheaper of the two is polystyrene garage doors. This is basically ridged rectangular cut pieces of foam that are laid into the garage door panels. Some models cover the foam with steal and some leave the foam exposed. The R-value is generally between R4 and R10. This is the most common Do-it-yourself type of insulation. The R-value of this type of door is lower in R-value compared to polyurethane insulation.

Polyurethane insulation is a foam type that is injected into the shell of the garage door panel. This product is a bit like the spray foam used around windows. This foam makes the panels very ridged and strong. The only way to get a polyurethane garage door panel is by buying one already insulated. The R-value is generally between R8 and R16.

2. Adding extra weight to a garage door

When adding any weight to a garage door the springs need to be adjusted or replaced. You will not need to worry about spring tension if less than 10% of the door weight is added. However, there is usually a minor adjustment to the garage door springs that should be made. Most of the time insulation will add up to more than 10% requiring that the springs need to be replaced.

3. The cost to insulate a garage door

If you opt to go for the DIY route, it will be a bit less money than to have the door replaced. Generally most people can get the insulation plus any other products required for less than a couple hundred dollars. Of course there is the problem of having the to replace the garage door spring(s). If you decide to change the garage door springs yourself, you can do it for less cost. This would run you around 60 to 140 depending on if yours is a one or two car garage. Most garage door companies will charge anywhere from $160 to $300 to replace the springs for you. 

4. Replacing the garage door panels

Another option to consider is to replace the panels, or “face” of the door. This is a good option if you want a better quality door, higher R-value and don’t mind spending a bit more money. A good point to note is that a door face comes with all new hardware, including hinges, rollers, cables, screws and springs. The cost of a new garage door face is usually about 85% of a whole new garage door. Keep in mind that most door companies will charge less for a door face installation than to replacer the whole door, tracks and all.

The Best Way to Insulate a Garage Door

There are a few things you will need to insulate a garage door:

  • Pre made polystyrene sheets
  • low expanding foam
  • heavy duty tape

You can buy polystyrene sheets at most big box stores. You will likely use 2 to 4 4×8 sheets depending on your door height and width. These sheets come in different thicknesses so be sure that the ones you buy are going to fit nicely into the garage door panels. Many non-insulated garage doors are 2″ thick, so try to get something slightly less thick than that as they need to fit into the panel.

Be sure to pre-measure every cut because the hinge preps will be in different spots on some doors making your cuts different lengths. Also, the panels can either be 24″, 21″, or 18″ depending on the height of your door so the height of your cuts could be different as well.

  • unplug your opener if you have one
  • use a tape measure and cut the pieces of foam exactly the length the foam needs to be from one hinge prep to the other. Then cut the foam height about a half-inch taller than the exposed inside of the panel(each panel will have a little return bent into the top and bottom for rigidness. Be sure to measure from the bottom of the top return to the top of the bottom return) 
  • using the spray foam, apply a half-inch bead around the perimeter on the inside of the panel hole. This will help not only seal cracks but also will act as an adhesive. Then using two hands slightly bend the foam board by pulling the middle toward you. Once you get enough of a bend in the board, the top should fit in
  • After you have all of the foam board installed you can use tape, if necessary, to hold the foam board from falling out when the garage door is open

Replacing The Springs


Now that you have installed the insulation the next step is to change the spring or springs. Although the process of changing springs is outside the scope of this article, we will quickly discuss the process.

Lift the door enough to put a scale under the door. If you have a double-wide door or a heavy door in general, you might need a heavy-duty scale. Take the spring tension of the door by using the proper winding bars. 

After all the spring tension is off, read the weight on the scale, and contact a professional garage door technician. A reputable garage door company will calculate the proper spring(s) for your specific door. Then all you have to do is replace the spring(s). Of course, it’s always a good idea to have a professional do this part for you.

That’s It! Now you have an insulated door that will function properly.

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