How to Patch Damaged Garage Door Insulation

Lead Image
  • 2-4 hours
  • Intermediate
  • 100
What You'll Need
Liquid nails
Utility knife
Insulation panel of the same R-value as the damaged panel
A ruler or straight edge
Putty knife or scraper
A tape measure
Thick piece of cardboard
120 grit sandpaper (optional)
Fiberglass body filler, such as Bond-o

There are two primary types of garage door insulation. The first is a reflective foil, which is one or two layers of an air bubble film sandwiched between two layers of reflective aluminum foil film. The second type is a panel. The most popular panel type of garage door insulation is the fiberglass panel. This article will walk you through the steps required to fix damaged fiberglass garage door insulation panels.

Step 1 - Cut Damaged Panel Section Out

Using the utility knife and the straight edge, cut out the damaged section of garage door insulation in a square or rectangular shape, to aid in replacement. Make your cuts as clean and straight as possible. A putty knife or scraper may be needed in order to completely remove the damaged section. Remove as much residual glue or bonding agent as possible.

Step 2 - Measure and Cut Replacement Panel Piece

Use the tape measure to come up with the dimensions of the area that you have just removed. Measure and mark these dimensions on the replacement panel. Carefully cut this piece out and dry fit it in the opening. Trim this piece and the opening as needed to ensure a snug fit.

Step 3 - Install Replacement Panel Piece

Liberally apply Liquid Nails or other appropriate glue or bonding agent to back of replacement piece and spread over the whole piece. Carefully insert the replacement piece into the opening and apply pressure for a minimum of five minutes to allow the bond to set up.

Step 4 - Allow Bond to Fully Cure

Use the piece of thick cardboard as a pressure distributor and wedge something behind it to maintain pressure on the replacement piece overnight to allow the Liquid Nails or other suitable bonding agent to completely cure to full strength.

Step 5 - For Aesthetics Only

For those not wanting the replacement patch to be visible, use Bond-o or fiberglass body filler to fill the gaps and allow the body filler putty to fully cure. Use 120 grit sandpaper and smooth out the filler joints. Paint as desired to cover the patch.

Safety Precautions

When working with fiberglass, it’s important to wear safety glasses and gloves, as the fibers are tiny and can be absorbed into the pores on your skin. Take special care when handling utility knives as they are razor sharp. If using a body filler to make the patched area aesthetically pleasing, be sure to allow for adequate ventilation.

This project can be safely accomplished in just a few hours and you can complete it alone. Be sure to always abide by safety guidelines when you work with glass or glue.