How to Caulk Cracks to Prevent Air Infiltration in Your Home

Cracks and gaps on the outside of your home cause air infiltration that increases the heating and cooling cost of your home as well as wasting energy. Since approximately one-third of a home’s air infiltration comes from small openings in walls, windows, ceilings, and doors; it’s important to locate and properly seal these gaps.

To caulk cracks on the outside of your home:

  1. Use a putty knife to scrape out any old caulk from the opening.
  2. Wipe off the crack with a rag to remove any dust.
  3. Apply a bead of quality exterior caulk to fill the gap.
  4. Smooth the bead of caulk with your finger, removing any excess caulk.

Watch this video to find out more.


  1. Found mouse urine and droppings behind the bathroom walls. I tore out drywall and insulation saturated with urine. Added bleach then vinegar and then lavender oil. Found gap 2” x 12” . Do I close the gap with wood from inside or outside? Do I chaulk where siding meets foundation on outside? All these years I smelled urine but I would just scrub the toilet with Clorox . I also blamed the cats. MF mice ?. Help


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