Measure the height and the width of the hollow-core door.
Cut a segment of rigid foam insulation that matches the measurements of the hollow-core door, using a craft knife. If you have a large door, you may need more than one piece of foam butted up next to each other.
Apply a thin coat of epoxy adhesive to the side of the door where the insulation will be affixed. Choose the side of the door that you see the least.
Press the insulation to the door, holding it in place for several seconds until the epoxy holds.
Allow the epoxy to cure for 24 hours.
Things You Will Need
- Measuring tape
- Rigid foam insulation
- Craft knife
- Clear epoxy adhesive
- Cover the insulation with a wall hanging or tapestry.