How to insulate a steel garage door

Garage doors are notorious for being cold and thin, totally uninsulated and allowing the outdoor temperatures to access the garage space fully. However, not all garage doors are identical or equal in composition.

Metal garage doors are made of either thin steel or aluminum, both of which are bad insulators and allow the cold and hot weather to permeate the garage.

Insulating a metal garage door requires a certain procedure and specific materials since metal is not the best material to adhere to.

The first step in insulating a metal garage door requires the materials you intend to use, and this is reliant on the type of metal door you own. Basically, a slat or roll-up metal door is not good for insulating since its constant toll-up, and roll down method will eventually lead to insulation breakdown that will also damage the motor. As such, if you own a roll-up garage door, consider replacing it with a solid plate door, one that can fold up and down without rolling into a cylinder.

There is really only one viable metal door insulation method around, and that is the use of polyurethane foam sheets. These are the predominant features of a garage door installation kit, and as such, are the most popular insulation material on the market today.

To purchase the right materials, you need to measure your door accurately, and then either order online or buy in the local hardware shop. Foam sheeting is not expensive, so always buy more than you need in case of cutting and fitting issues. If you buy a garage insulation kit, buy an extra sheet of insulation material for spare, it’s better to have more than less in this case.

Once you have the materials, either in kit form or bought individually, check the list to see you have everything. You will need the following:

  • Enough foam sheeting to cover the entire door
  • box cutter to cut the foam
  • Adhesive tape to apply the foam
  • Glue to stick the foam permanently

Once you have these materials, here is how you use them to install insulation on a steel garage door.

Step 1: Clean the door

This means totally clean it removing the grime and dust from the surface of all the panels as well as the sides and hinges. After cleaning the surface, dry it down completely to assure a secure adhesive grip if your door is extra-large consider using a garden hose and sponge with detergent. Lather on the sponge over the door and then spray it down. Clean it off with rags and let it stand for a while until totally dry. Obviously, it’s best to perform insulation in hot, dry weather.

Step 2: Measure each panel and note the sizes, write them down and give each panel a letter for identification. Use a tape measure and measure the panels individually. If you decide to just cover the entire door over the seams or design, then you only need to take a full measurement. However, consider that a large fixture requires two people and is extremely hard to accomplish even for a professional.

Remember, if your door is a roll-up type, don’t insulate it before you talk to a professional, these doors will damage when incorrectly insulated, and insulating them is only done by a professional with experience, if at all.

Step 3: Cut the foam board you purchased, whether from a kit or individually and make sure you bought a high rater board (R rating) The higher the R-rating, the more insulation you get from the board.

Its also best you get a foam board with an aluminum foil backing, this works to help prevent heat loss in the winter and promotes heat reflection in the summer, so your garage will either be hotter in the winter or cooler the summer.

Using the box cutter, cut the foam into the pre-defined sizes and lay them out for preparation to apply.

When cutting use a metal ruler, and if the board is thick and hard, consider investing in a power saw. Make sure you provide a maximum dimension cut, you want a tight fitment, not a loose one.

Step 4: apply adhesive to the door surface within the frame you intend to place the foam. Always apply each adhesive coating before you apply the foam, and don’t apply the adhesive in one go to all the door, parts will dry as you progress along the door, work one panel at a time.

Step 5: Once you have all the pieces cut and ready, use the railings that most garage doors come with to act as the natural frames for the insulation. These railings are anywhere from 2.5 cm to 5.1 cm deep.

Place the foil facing inwards towards you; if you have double sided foil, then this doesn’t matter. And firmly squeeze the insulation into the frame. Some railings might require you to make some relief cuts, that’s why you have a larger sized fitment and not an undersized one. Once you manage to “pop” the board past the railings, you can move onto the next stage.

Press the board firmly against the glue and apply pressure along all the board until it is firmly held onto the adhesive evenly across the entire surface.

Continue this process until the door is completely covered.

Step 6: seal the sides, make sure that the door frame is also sealed along its seam to the wall. You can use standard silicone sealant or foam insulation that sprays on and solidifies after application.

Conclusions: Some garage insulation kits come with preset sized boards for standard or universal fitment. Only buy a kit if you are 100% condemned that it fits your garage door. Applying the garage door kit is similar to that of the DIY version, but with less cutting.

Leave a Comment