How to Keep it Tight in Older Homes - Air Infiltration

If you are considering buying an older home or you currently live in one it only takes a few minutes to seal those drafty cracks and save on your energy bills.

Hidden air leaks cause some of the largest heat losses in older homes. Common air leakage sites include:

• Plumbing penetrations through insulated floors and ceilings
• Chimney penetrations through insulated ceilings and exterior walls
• Fireplace dampers
• Attic access hatches
• Recessed lights and fans in insulated ceilings
• Wiring penetrations through insulated floors, ceilings, and walls
• Missing plaster
• Electrical outlets and switches, especially on exterior walls
• Window, door, and baseboard moldings
• Dropped ceilings above bathtubs and cabinets

The best material for sealing these hidden air leaks depends on the size of the gaps and where they are located. Caulk is best for cracks and gaps less than about 1/4" wide.

Expanding foam sealant is an excellent material to use for sealing larger cracks and holes that are protected from sunlight and moisture. Today's products are safe for atmospheric ozone. Backer rod or crack filler is a flexible foam material, usually round in cross-section (1/4" to 1" in diameter), and sold in long coils. Use it for sealing large cracks and to provide a backing in very deep cracks that are to be sealed with caulk.

Use rigid foam insulation for sealing very large openings such as plumbing chases and attic hatch covers. Fiberglass insulation can also be used for sealing large holes, but it will work better if wrapped in plastic or stuffed in plastic bags, because air can leak through exposed fiberglass. Specialized materials such as metal flashing and high-temperature silicone sealants may be required for sealing around chimneys and flue pipes. Check with me if you're unsure about fire-safe details in these locations.

We provide comprehensive energy efficiency inspections.