Existing buildings in Canada will make up the bulk of insulation and air sealing work for the next few decades. Each one will require a thorough inspection to identify potential issues before the energy retrofit can be done.

A baseline energy audit can identify performance issues with an older building but a careful visual inspection may reveal other issues, such as:

• Spacing of framing not on common centres. Older structures may not have 16" or 24" on centre spacing, which may make friction fit and barrier installation challenging.
• Preexisting air or vapour barriers. Additional insulation of certain types may change the effectiveness of those barriers or move the dew point, potentially leading to condensation.
• Inadequate attic ventilation. The unconditioned attic space should keep the ambient temperature of the outdoors, with proper vents on soffits, between rafters and on the upper roof. Look for blocked cavities where walls meet the roof structure.
• Chimneys, wiring or mechanical equipment in attic spaces. Any areas that need to be isolated safely or treated with heat resistant materials should be identified.
• Clusters of framing that will be difficult to air seal. Corners, floor headers and beams may require special materials for proper sealing and insulation.
• Interrupted continuity of surfaces. Bay window bump outs, fireplaces, penetrations for utilities and other shape changes in a building envelope make for challenges in sealing and insulation. Identify these areas and strategize for maintaining the continuity of the various layers.