Foam board is thicker than reflective paneling, so it will be more effective and may also be more expensive. Both foam board and reflective paneling should be available from your local hardware store.
Garage door insulation kits will usually come with fiber batting, which will have a much higher R-value than other options. The higher R-value an insulation option has, the more effective it will be at insulating.
If you install the insulation with the foil facing into the garage, it will reflect the heat inside the garage back and keep the room warmer. Use this method if you live in a colder area. If you install the insulation with the foil facing outward, it will reflect the heat from the sun away from the door, keeping your garage cooler. Use this in an area that gets hotter more often. If you live in an area without extreme temperatures, or you want to be able to regulate the inside of your garage more easily, try and find insulation with foil on each side.
It may also help to spray your garage door down with a garden hose, the same way you would clean a car. Spray it down and then wipe it dry with a rag or spare towel to clean your door further. You could also clean your garage door with a pressure washer if you have one available. Test it on a small space first to make sure it doesn’t damage the door, before cleaning the whole door. Use a rag or spare towel to dry the garage door once finished. Make sure your garage door is completely dry before you begin installing any insulation.
Always measure the panels individually, as they may be different dimensions in different places across the garage door. Measure each panel and take a separate measurement. If your garage door doesn’t have panels built into it or is just a singular flat surface, you can still use foam board insulation. Measure the internal size of your entire garage door for a guideline on how much insulation board you will need. If you have a garage door that rolls up into the ceiling, foam board and most other easy types of insulation will be too bulky for the mechanisms holding your door. Talk to a garage door specialist to investigate your options, or to look into replacing your door with a pre-insulated one.
Some hardware stores will offer to cut the boards to size for you. Bring the measurements you’ve taken of the door with you in case your local hardware store offers this service.
Foam board and reflective paneling won’t often have exceptionally high R-values, but they are the cheapest and easiest options for the level of insulation you get with it. If you live in a place without a lot of extreme temperatures, either should be enough. The foil backing will work to help reflect the heat, helping to keep your garage insulated further.
If the sides of your foam board are slightly crooked or uneven, grind them along a hard surface like the concrete floor of your garage to sand them down and even them out. If you have a circular saw or something similar, you can use this to easily cut the foam boards to size. You don’t need to cut all the way through the foam board to trim it to size. Cut at least halfway through on a straight line, and bend the board to snap it evenly along that line. Cut the reflective paneling on a piece of cardboard or something similar to avoid dulling the blade as you cut through it.
Depending on the size and shape of the metal railings, you may need to make some relief cuts into the edges of the foam board so that it can slide into place easily. Use a craft knife or something similar to cut down the edges of your foam boards so they fit into place. If you cannot get the foam boards into the metal railings, you can cut the board in half lengthways and try to fit the two halves in independently. This will give you a straight edge to work with, and shouldn’t reduce the effectiveness of the insulation as long as the board remains snug. If you are using reflective paneling, add some double-sided tape to the door first to help it hold securely for longer.
Make sure you leave around 1 inch (2. 5 cm) of space between the foam board and any hinges that the door will bend on. The door should be able to close without different panels of foam board touching each other. For extra security, you can also put adhesive over the center of your foam board or paneling.
Make sure your door is completely clean and dry before you begin installing insulation. Any dirt or grime on the inside of the door will prevent the insulation from sticking, and any will be trapped behind the insulation once it’s installed. You could also use a pressure washer to clean the garage door. Test it on a small area first to make sure it doesn’t damage the door, before spraying down the entire surface. Use an old towel or a rag to wipe away excess water before leaving it to dry completely for 3-4 hours.
If your door is broken up into panels that are separated by a metal railing, measure each of the panels individually rather than measuring the whole door.
Depending on the size of your door, you may need to purchase two insulation kits. If you have a double garage, for example, it’s likely you’ll need multiple kits to insulate the whole door. Purchase the insulation kit with the highest R-value for the best insulation. If you’re unsure about which kit to buy for your door, feel free ask someone at your local hardware store for assistance. You may be able to buy the individual parts of the kit independently, but this will often be more difficult than purchasing the right kit. Ask at your local hardware store to look into your options.
The retaining pins will be long plastic or metal spikes on a wide and flat base that can be stuck to your door. They will help hold your insulation in place. The pins don’t need to be lined up perfectly, as long as they are roughly evenly spaced and divided across each panel. If you don’t have panels on your garage door, use the sheets of batting insulation as a guide to break your door up into different sections. Install your retaining pins in the same method, but spread out over these sections rather than across prebuilt panels.
If your door is without panels and you installed the retaining pins based on the size of the batting, you shouldn’t need to trim it down at all. For extra safety, wear cut-resistant gloves while working with the batting.
If your batting is only covered in foil or plastic on one side, make sure it is that side that is facing towards you when installing the batting. This will both make the finished door look better, as well as improving the insulation. If you don’t have metal railings surrounding the panels or sections of your door, you can simply press the batting onto the retaining pins to hold it steady as you continue working.
If there is foil or plastic on both sides of the batting, make a deeper incision so that the pin can push through both layers of protection and emerge on the other side.
The fasteners will stop the batting from falling out, as well as softening the tips of the retaining pins. Different kits will have different retaining pins and fasteners. Check the manufacturer’s instructions for your specific garage door insulation kit for advice on how to attach your fasteners.
Aluminum foil tape will hold the batting place and help insulate the gaps between each piece of batting. It should be available at your local hardware store or online.
