What is thermal bridging and how does it affect building performance?

1 What is thermal bridging?

Thermal bridging is a phenomenon that occurs when heat flows through a path of least resistance in a building envelope, bypassing the insulation and creating a thermal imbalance. For example, if you have a concrete wall with metal studs and insulation between them, the metal studs will conduct more heat than the insulation, creating a thermal bridge. Thermal bridging can cause several problems, such as increased energy consumption, reduced thermal comfort, condensation, mold growth, and structural damage.

2 How to identify thermal bridging?

One of the ways to identify thermal bridging is to use a thermal imaging camera, which can capture the surface temperatures of different parts of the building envelope. By comparing the images with the design drawings, you can spot the areas where the insulation is compromised or missing, and where the heat is escaping or entering. Another way to identify thermal bridging is to use a hygrometer, which can measure the relative humidity and dew point of the indoor air. By comparing the readings with the outdoor conditions, you can determine if there is a risk of condensation or mold growth due to thermal bridging.

3 How to prevent thermal bridging?

The best way to prevent thermal bridging is to design and construct the building envelope with continuous insulation, which means that there are no gaps or breaks in the insulation layer. This can be achieved by using materials that have low thermal conductivity, such as wood, plastic, or foam, and by avoiding or minimizing the use of materials that have high thermal conductivity, such as metal, concrete, or stone. Additionally, you can use thermal breaks, which are insulating elements that separate the thermal bridges from the rest of the building envelope. For example, you can use plastic or rubber washers, spacers, or clips to isolate the metal studs from the concrete wall.

4 How to mitigate thermal bridging?

If you cannot prevent thermal bridging completely, you can still mitigate its effects by using some strategies. For instance, you can increase the thickness or the R-value of the insulation, which will reduce the heat loss or gain through the thermal bridges. You can also use air barriers, vapor barriers, or moisture barriers, which will prevent the air, water vapor, or liquid water from moving through the building envelope and causing condensation or mold growth. Furthermore, you can use ventilation, heating, or cooling systems, which will control the indoor temperature and humidity and improve the thermal comfort.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?