seal holes, cracks, and penetrations

materials needed

• One-part urethane caulk, acrylic latex caulk with silicones, paintable silicone caulk, or other caulk with at least a 20-year life
• Backing material––such as foam backer rod
• Spray foam sealant––e.g., Great Stuff Polycel 1® or Touch n’ Foam®
• Sheet materials such as insulation board, plywood, or cardboard to cover large holes

tools needed

• Caulk gun
• Utility knife
• Carpenter’s tool belt
• Saw

required skills: Simple handiwork, perhaps some basic carpentry

annual energy savings: $130 to $180/house

average time required: varies widely

project steps

1. Use caulk or spray foam sealant to seal cracks or holes smaller than a pencil width in the ceiling, floor, or exterior walls. Seal holes on both the inside and outside surfaces of walls.
2. For larger openings, use spray foam sealant or fill the crack with backing material and caulk the surface.
3. Use sheet materials, such as cardboard, insulation board, or plywood, to cover large holes. Seal the edges of the sheet materials with caulk or spray foam sealant. Be sure to seal openings between the attic and house, and between the crawl space or basement and house.