What Is Thermal Bridging? Causes, Signs and Solutions
Thermal bridging occurs when heat travels through a building material that conducts heat more readily than the insulation surrounding it. Common thermal bridges include wood or metal framing, concrete slabs, lintels, balconies and connections between walls, floors and roofs.
These areas can reduce the overall thermal performance of a home, create uncomfortable cold surfaces and increase the possibility of condensation when warm, moisture-laden indoor air contacts colder building materials.
What Causes Thermal Bridging?
Most insulated walls contain structural framing members. Although insulation may be installed between the studs, heat can still travel through the framing itself.
Common thermal-bridge locations include:
- Wood or metal wall studs.
- Floor and rim joists.
- Window and door lintels.
- Concrete foundation walls and floor slabs.
- Balconies and exterior structural connections.
- Wall-to-roof and wall-to-floor transitions.
- Areas where insulation is missing, compressed or displaced.
Why Is Thermal Bridging Important?
Thermal bridging creates a path through which heat can escape during winter or enter during summer. This can reduce comfort and increase the amount of energy required to heat or cool the home.
Possible effects include:
- Cold wall or ceiling surfaces.
- Uneven room temperatures.
- Higher heating and cooling demand.
- Visible framing patterns on walls or ceilings.
- Condensation at cold surfaces.
- Moisture-related staining or deterioration.
- Reduced effective insulation performance.
What Thermal Bridging Looks Like During Thermal Imaging
Thermal imaging can sometimes reveal temperature patterns associated with wall studs, roof framing, missing insulation and air leakage. In the images below, cooler framing members appear as visible lines across the walls and ceilings.
Can Thermal Imaging Confirm Missing Insulation?
Thermal imaging identifies temperature differences at accessible surfaces. These patterns may suggest thermal bridging, missing insulation, compressed insulation, moisture or air leakage.
However, a thermal camera does not see through walls and does not independently confirm the exact cause of every temperature difference. Results must be interpreted according to indoor and outdoor conditions, temperature differences, sunlight, heating operation and the construction of the building.
Thermal Bridging and Condensation
During cold weather, thermal bridges can create colder interior surfaces. When warm indoor air contacts these surfaces, condensation may develop if the surface temperature falls below the dew point.
Repeated condensation may contribute to:
- Water staining.
- Paint or finish deterioration.
- Wet or damaged insulation.
- Wood deterioration.
- Mould-like growth.
- Reduced indoor comfort.
Indoor humidity, ventilation, air leakage and insulation levels should all be considered when investigating condensation.
How Can Thermal Bridging Be Reduced?
One of the most effective methods is to install a continuous layer of insulation across structural framing. Continuous exterior insulation can reduce direct heat flow through studs, rim joists and other framing components.
Depending on the building and renovation project, possible improvements may include:
- Installing continuous rigid or mineral-wool insulation.
- Improving insulation at rim and floor joists.
- Sealing air leakage around wall and ceiling penetrations.
- Correcting missing or displaced attic insulation.
- Improving insulation around windows and doors.
- Insulating exposed foundation walls where appropriate.
- Maintaining suitable indoor humidity and ventilation.
The complete wall or roof assembly should be considered before adding insulation. Improperly positioned low-permeance materials may restrict drying and contribute to trapped moisture.
When Should Thermal Bridging Be Investigated?
Further investigation may be useful when homeowners observe:
- Cold exterior walls or ceiling areas.
- Recurring condensation.
- Visible framing patterns through finishes.
- Uneven indoor temperatures.
- Unexpectedly high heating costs.
- Ice accumulation or snow-melting patterns on the roof.
- Suspected missing insulation.
What Can a Home Inspection Identify?
A home inspection can identify visible insulation deficiencies, condensation, moisture staining, air-leakage locations and other conditions associated with the building envelope.
Thermal imaging may be used as a supporting tool where conditions are suitable. It does not replace visual inspection, moisture testing or invasive investigation where concealed damage is suspected.
Natural Resources Canada provides additional information about thermal bridging, insulation and heat flow in its Keeping the Heat In homeowner guide.
Schedule a Thermal Imaging Inspection
Inspec-Pro Home Inspections provides residential inspections and thermal imaging services throughout Ottawa, Gatineau, Outaouais and surrounding communities.
Learn more about our thermal imaging inspection services or request an inspection quotation.
Call 819-962-5880 or email info@inspec-pro.ca.