Why thermal bridges matter during home renovations

If you feel a draft in one spot in your home, it could be due to a thermal bridge. Discover why you should keep thermal bridges in mind during home renovations.

A thermal bridge, also known as a cold bridge, is a term used to describe weaknesses within a building’s structure where heat or cold transfer at a considerably higher rate than through the surrounding envelope area.

A building’s envelope is everything that makes up the shell and skin of the building. These components are what separate the exterior of the building from the interior. The building envelope can also be defined as the components that separate conditioned areas from unconditioned space. Key elements of a building envelope include the foundation, windows and doors, walls (interior and exterior) and roof systems. The basic function of a building envelop is adding structural support, controlling moisture and humidity, regulating temperature and controlling air pressure changes. When a building envelope is designed poorly and allows external elements to penetrate through the insulation, a thermal bridge occurs.

• Junctions between walls and floors, and walls and roofs.
• Reveals around windows and doors.
• Holes made by pipes and cables.
• Studwork in timber frame walls (interrupting the insulation).
• Steel wall ties in masonry construction.

Often times homeowners with homes that suffer from thermal bridging do nothing about it, because they really have few options. Thermal bridging can only be avoided during the construction of the house, so if builders and engineers don't take this into consideration, the occupants suffer from the thermal bridging.

Effects of thermal bridging typically appear several years after the building’s construction and can cause excessive moisture, creating mold or mildew. Extreme heat loss will lead to unnecessary energy usage as well as serious material degradation issues such as corroding steel beams, crumbling bricks and failing exterior insulation finishing systems.

For most homeowners the perception is that this is inevitable in most homes and that it's something they should just deal with.  Understanding how thermal bridging effects the energy, moisture and heat distribution within your home can help you make more educated decisions when you are in the process of renovations or installing insulation.