What is Thermal Bridging?

Thermal bridging refers to areas in a building's structure where heat flows more easily than in the surrounding materials, typically due to a material with higher thermal conductivity. In a well-insulated structure, most materials resist the transfer of heat, but thermal bridges act as a "shortcut" for heat flow, leading to energy loss and potential issues such as condensation, mold growth, and reduced overall building comfort.

Common places where thermal bridges occur include:

• Steel or concrete beams passing through insulated walls or floors

• Window frames that are not well-insulated

• External walls that are interrupted by poorly insulated or conductive materials (e.g., steel studs, uninsulated concrete, or masonry ties)

• Corners where walls meet the floor or ceiling, especially if insulation is poorly installed

How to Minimise Thermal Bridging:

1. Continuous Insulation:

   • One of the most effective ways to reduce thermal bridging is to use continuous insulation across the exterior of the building. This helps to create a seamless barrier that prevents heat from escaping through conductive materials. For example, rigid foam boards or spray foam insulation can be applied across walls, roofs, and floors.

2. Use of Thermal Breaks:

   • Introduce materials with low thermal conductivity (such as insulation) between conductive elements (e.g., steel studs or metal connections). Thermal breaks can be added in places like window frames, wall anchors, or structural components.

3. Proper Detailing Around Building Penetrations:

   • Ensure that penetrations in the envelope (e.g., for pipes, electrical cables, or HVAC ducts) are well-insulated and sealed to avoid gaps that would allow heat to pass through.

4. High-Performance Insulation Materials:

   • Choose insulation materials with high R-values (resistance to heat flow) for areas vulnerable to thermal bridging. Examples include rigid foam, spray foam, mineral wool, and fiberglass batts with higher insulating properties.

5. Avoid Direct Contact of Conductive Materials:

   • Avoid placing conductive materials such as metal studs or structural elements in direct contact with the building's external cladding or insulation. If needed, use materials like thermal breaks or clips to separate these conductive elements from the building envelope.

6. Advanced Framing Techniques:

   • Using advanced framing methods like staggered or double-stud framing can reduce the number of studs in a wall, reducing the overall thermal bridging from studs to exterior surfaces. This allows more room for insulation and reduces conductive heat transfer.

7. Insulated Doors and Windows:

   • Select high-performance windows and doors that have low U-values (rate of heat transfer). Look for triple-glazed windows with thermal breaks in the frames and weatherstripping to reduce heat loss.

8. Use of Aerogel or Vacuum Insulation Panels:

   • In high-performance construction, aerogel or vacuum insulation panels (VIPs) may be used as highly effective thermal breaks in areas where conventional insulation materials may not be practical or sufficient.

9. Thermal Bridging Calculations:

   • Perform thermal bridging analysis (using software tools) to identify where bridges occur in the design phase. This allows for the identification of problematic areas before construction begins, making it easier to incorporate design changes.

By addressing thermal bridging effectively, you can improve energy efficiency, prevent condensation issues, and enhance overall comfort in a building.