The foundation of a building is the anchor to the earth. Older buildings may have foundations of stone, brick, concrete or wood. In all cases, the foundation must be in good condition before insulation and air sealing materials are applied.

Important Safety Considerations for Foundations:

• The soil or landscaping that surrounds a foundation is called the "grade". Basements are below grade, while upper storeys are above grade. The grade must slope away from the building to ensure proper drainage.
• Water infiltration in older foundations may show up as damp air, wet floors or efflorescence (white stains) on the structure;
• Spalling - water soaked masonry that goes through freeze / thaw cycle may deteriorate to the point of cracking, with pieces falling off.
  
• Joints between bricks or stones may require re-pointing to replace mortar - watch for telltale piles of sand around the bottom of masonry walls;
• Wherever wood elements touch stone, brick or concrete, the foundation and floor system should be carefully inspected for signs of rot.
  
• Movement / shifting may occur in older foundations because of water pressure, mortar failure and environmental changes. Cracks and distorted surfaces may be a sign of foundation movement.
• Cracks and failure of parging layers on the exterior of the foundation may also be signs of trouble.
  

Insulating foundations and basement spaces may happen from the interior OR the exterior, though an exterior application on an existing building might be very costly.

Thermal, air tight and vapour control strategies on foundations must always factor in the removal of water. Whether in liquid or vapour form, most basements will have water present.