DIY Projects

Project File #11
Do It Yourself
As Soon As Possible
Better comfort, lower energy costs

Air sealing and insulation your foundation walls help shield your home for better energy efficiency.

If your basement and crawlspaces are improperly sealed, your home may be losing a lot of energy. These losses, in turn, can lead to higher energy bills and a less comfortable home. This project can help protect you against both.

Project Overview

Tools and Materials:

  • Utility knife
  • Table or circular saw
  • Caulk gun
  • Measuring tape
  • Lights
  • Straight edge or markers
  • Foam/caulk/construction adhesive/duct mastic
  • Insulation—cavity batts or rigid foam board insulation
  • Sheathing—OSB/plywood or code-approved foam board
  • Fasteners—screws with washers or button-capped nails


  • Dust mask/respirator
  • Gloves
  • Safety glasses
  • Kneepads
  1. Inspect your home’s foundation wall and rim joists, keeping a particular eye out for things like water, sewer, and gas lines, electrical wiring, and other penetrations that may lead to air leaks.
  2. Once you’ve identified those areas where you may be losing energy through poor air seals, use caulk or rigid insulation board to fill gaps and close the spaces around penetrations.

Download Project File

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