July 17, 2021

DIY Insulation for Your Basement Or Garage: A Guide for Utah Homeowners

With summer heat setting in, many of us are looking for ways to stay cool through the heatwave. While hiding inside your house is certainly an option, you may have projects you want to work on in your basement or garage. And while the rest of your house should be well-insulated, these rooms are often left out, making them very uncomfortable during hot or cold weather.

Luckily, insulating these spaces is a fairly straightforward process that you can tackle yourself on the weekend. Read on to discover some DIY insulation tips that will make your summer much more comfortable.

Calculate Your Square Footage

The first thing you need to do when you’re insulating a garage or basement is to calculate your square footage. Unlike normal square footage calculations, these measurements will not focus on the area of the room. Instead, you’ll need to figure out the square footage of all your walls and ceilings combined.

Start by measuring each of your walls from floor to ceiling and from end to end. Multiply the height and width of each wall, and then add all those products together to get your total wall square footage. Then measure your ceiling either by length and width or from the top of the walls to the peak of the ceiling and from front to back and perform the same calculation.

Figure Out Your Insulation Width Needs 

Don’t put your tape measure away just yet; you’ll need it to work out how wide your insulation should be. You’ll need to measure the distance between the studs in your garage or basement to calculate this. Measure from the center of one stud to the center of the next and find insulation that’s a little bigger than that distance.

Of course, if you already have solid walls in your basement or garage, you may not need to do these calculations. In this case, if you plan to use rolls of insulation (which may not be your best option), take a look at the length of each of your walls. Figure out which width will fit best in your space without wasting too much insulation at the end of the wall.

Pick the Right Insulation

There are several different types of insulation you’ll need to choose from when planning your garage or basement upgrade. Which one you use will depend on your specific space and what will best fit your needs.

Blanket Insulation 

Blanket insulation includes batts and rolls, such as you see with fiberglass insulation. Blanket insulation can also be made of mineral wool composed of rock or slag, plastic fibers, or natural fibers.

Blanket insulation can be used in a variety of unfinished walls, as well as in floors and ceilings. It fits between studs, beams, and joists and is relatively easy to install yourself. It’s relatively inexpensive, and it comes in standard widths that will fit between almost all studs, including those in your garage.

Foam Board 

If you’re looking for a quick, easy, light insulation solution, foam board is a fantastic option. You can install it on unfinished walls, floors, and ceilings, as well as on low-slope roofs with no vents. Foam board insulation is usually made of polystyrene, polyurethane, or polyisocyanurate.

In order to be fire-safe, foam board must be covered by at least a half-inch of gypsum board or some other fire-resistant material. If you use it outside, you’ll need to cover it with a weatherproof facing to keep it from degrading over time. However, foam board provides a lot of insulating power in a very thin layer and can help to block thermal short circuits.


If you already have finished walls in your garage or basement, don’t worry; you still have insulation options available to you. Loose-fill insulation can be blown into your space after it’s already completed or to fill in hard-to-reach spaces. It’s usually made from cellulose, fiberglass, or some sort of mineral wool.

The major downside of loose-fill insulation is that you can’t install it yourself, since it requires special equipment. However, it is fantastic for insulating spaces that have already been finished. You can also use it to insulate around obstructions and irregularly shaped area, since it fills the area you blow it into without requiring cutting or nailing.

Sprayed Foam

If you’ve ever watched HGTV, you’re probably familiar with the mesmerizing process of installing spray foam insulation. This expanding foam gets sprayed onto unfinished walls and ceilings or into finished walls. The foam is usually made of cementitious, phenolic, polyisocyanurate, or polyurethane.

For large insulation projects, you’ll need to have spray foam insulation professionally installed. However, you can buy small cans of expanding spray foam to fill gaps and cracks in your basement or garage. This is another fantastic option for increasing insulation in spaces that have already been finished.

Cut Your Insulation to Fit

Once you’ve decided what sort of insulation you want to use, you’ll need to start fitting it into your space. In the case of sprayed or blown-in insulation, you’ll be able to simply fill your space with the material. If you’re doing this yourself, be sure you make sure you have the appropriate density of filling. 

If you’re using blanket or foam insulation, measure the distance between your studs and cut your insulation to fit if needed. You may want to use a utility knife for this job, and it’s a good idea to wear gloves, especially if you’re working with fiberglass. Pay special attention to the corners of your space, as these may not be a standard width.

Attach to the Studs

Once your insulation is cut to size, you’ll be ready to start attaching it to your garage or basement walls. If you’re using blanket insulation, lay the pieces in place between the studs with the paper facing out. Use a staple gun to attach the paper to the sides of the studs – you’ll want the front free for attaching drywall.

If you’re using foam insulation, you can simply slide it between the studs of your garage or basement. It should be a tight enough fit to hold the board in place, but not so tight that the foam begins to tear. The board is light enough that it will hold itself in place, even without fasteners. 

Install Retainer Pins on the Door

Once you get your walls insulated in your garage, the job is only half done. You also need to insulate your garage door if you want your space to stay warm and cool. You’ll likely want to use blanket insulation for this job, though you can also use foam boards if you like.

You’ll need to begin by attaching retainer pins to your garage door to hold the blanket insulation in place. Mark a spot that’s a foot away from the edge of each panel and halfway between the horizontal rails. Peel the backing off your retainer pins and press them into the spot you measured, placing two pins on each door panel.

Cut Your Insulation

Once your retainer pins are in place, you’ll have to measure and cut your insulation to fit into your garage door. Start by measuring the space where the insulation will fit on the inside of your garage door. Mark these measurements out on your batting, laying the vinyl side down on the floor to do this. 

With your cutting lines marked, use a piece of plywood and a straight edge to compress your insulation. Use a utility knife to cut along your mark, making sure to wear gloves if you’re working with fiberglass. If you’re using foam board, simply slice through it with a utility knife and fit it in place on the doors. 

Lock the Batting in Place

Now that you have your batting cut to size, it’s time to lock it onto your doors. If you’re using foam board insulation, you can either use the same retainer pins you would for blanket insulation or use spray adhesive to hold it in place. Once more, make sure your fit is tight enough that it will hold easily in place, but loose enough that it won’t break the foam.

If you’re using blanket insulation, center your sheet on your garage door panel with the vinyl lining facing out. Push the insulation down on the retaining pin until the pin punctures through the lining. Then push the cap down on the retaining pin until you feel it snap into place, and repeat on every panel of your garage door. 

Mount Weather Stripping

Getting insulation in place can help keep your garage warmer or cooler, but it will only do so much if you have air leaking in around your garage doors and windows. You need to make sure to put weather stripping in place to seal any gaps that might let out your climate-controlled air. Start by placing foam weather stripping under all your windows to seal them tightly shut.

Next, get some vinyl weather stripping and place it at a 45-degree angle against the outside of your garage door. Tack it in place with nails (only driving them partway in), and then push on the door in several places to see if the seal will be broken during strong winds. Adjust the weather stripping as needed and then drive the nails in fully.

Insulate Your Ceiling 

Once your walls and doors are insulated, you’ll need to turn your attention to the rafters. If your garage has a closed-in ceiling, the easiest type of insulation to install will be loose-fill or blown-in insulation. You can hire a company to install this insulation for you, or you can use the same blanket insulation method we discussed for your walls. 

If you have open rafters, foam board insulation may be your best bet for insulation. You will need some sort of fastener to hold the sheets in place, and you’ll need to account for things like breathing room and moisture control. This is a job that’s still best left to the professionals, who know how to manage all those issues. 

Discover More DIY Insulation Tips

Insulating your basement and garage can make your home much more comfortable. Make sure you find the best type of insulation for your project, and always attach it securely in place. And don’t forget your ceilings, floors, and doors when you’re insulating; they can let in just as much cold air as the walls can. 

If you’d like to find more DIY insulation tips, check out the rest of our site at Green Home. We can help you live more comfortably while saving money on heating and cooling. Get a quote on your DIY insulation project today and discover how you can save the most on your heating and cooling expenses.

Top linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram