How to Use R-Tech Foam for Garage Insulation

Person installing foam insulation sheets
  • 2-30 hours
  • Intermediate
  • 100-500
What You'll Need
Measuring tape and pencils
Table saw
R-Tech insulation: Insulfoam (TM) or other brand
Self-adhesive Velcro strips
4-foot by 8-foot plywood strips, 2 inches wide
Wood planks, 8 feet long by 2 inches by 1-1/2 inches deep
Power drill with masonry bits
2-1/2 inch wood screws
1-inch galvanized nails
1-inch finishing nails
Claw hammer
Eye goggles

Upgrading your garage insulation may help you save a bundle on energy costs throughout the year. A poorly insulated garage can allow hot air into your home in summer and permit expensively warmed air to escape in the winter. You can install R-tech foam insulation in your garage in a weekend by following these guidelines.

Step 1 - Determine the Garage Area You Need to Insulate

If your garage protrudes beyond your house and has no insulation, add the R-tech Insulation to both garage walls and the garage door. If the garage is contained within the body of the house, add insulation to the external garage wall and the garage door. In an insulated garage, you need only add R-tech foam to the garage door back. Measure carefully to determine the number of two by four-foot insulation panels you will need. The 1 1/2 inch thick panels will fit the garage door best.

Step 2 - Cut and Insert the Insulation Panels to Fit Your Garage Door Style

If your garage door has several windows, measure and cut thin strips of insulation to fit around them. Secure the insulation strips in place with adhesive Velcro strips. Cut the large panels on the table saw to fit the segments of the garage door, and slip them into place around the edges of the door first. Fill in the rest of the door with panels that you have cut to fit.

Step 3 - Prepare a Grid for the Garage Wall Insulation

sheets of foam insulation

If you need to add insulation to the garage walls, too, first you must build a grid to hold the panels in place. Measure the wall area and buy sufficient plywood strips to make a grid of panels 23 by 47 inches in size. You can then insert the insulation sections without having to trim each to fit the grid. Attach the grid to the wall at top and bottom and across the center of the wall on wood slats 1 1/2 inches thick so the insulation will fit in snugly. Fasten the thin plywood strips in rectangles, sized as noted above to the slats, with one-inch galvanized nails.

Step 4 - Attach the Insulation

Slip the insulation sections into the wall grid starting at the wall perimeter, then filling in the center of the grid for each wall. Secure the plywood grid to the insulation panels with one-inch finishing nails.

This insulation job should cost less than $500, and will pay for itself quickly in energy savings. R-tech polystyrene foam is recommended for insulating garages because it is weather-resistant, lightweight, resists cracking and crumbling, and is easy to handle. This foam can be installed without using noxious glues or adhesives, and is inexpensive, at an average cost of just $20 for a 4 x 8 foot standard sheet.