Thermal bridges: how to identify and fix them?

What is a thermal bridge?

A thermal bridge is a weakness in the building's insulating envelope. At this spot, the barrier against heat transfer is broken or less effective, which promotes energy losses. This insulation defect causes a feeling of discomfort, but can also lead to damp and even mould.

These critical areas are frequently located at structural junctions: wall-ceiling connections, wall-roof corners, window frames or protruding zones such as balconies.

To put it simply: imagine your whole house is well insulated, except at a few spots where heat escapes as if through an invisible crack. Those gaps are thermal bridges. They generally appear at points where the thermal resistance of the materials is insufficient or interrupted, such as at the junctions between walls and floors.

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Where do thermal bridges hide in construction elements?

The places where heat escapes are not always visible to the naked eye. Here are the most common places where they can be found:

Window frames:

Poorly installed frames or badly executed insulation create a noticeable chill around openings.

Intermediate floors:

The junction between external walls and floor slabs is a classic source of thermal bridges.

Balconies and protruding elements:

These elements pass through the thermal envelope of the building and often create weak points.

Attics and roofs:

A poorly insulated roof or badly handled roof-wall junctions can generate significant losses.

Basements and cellars

The contact between the cold ground and the walls of the building constitutes a major thermal imbalance.

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What are the different types of thermal bridges?

Several typologies can be distinguished, according to their origin:

Geometric: caused by the shape of the building, these bridges appear even with continuous insulation, due to variations in the structure.

Connection (or point) bridges: they appear when a construction element crosses or interrupts the thermal insulation.

Execution bridges (or installation defects): due to installation errors or careless workmanship, often during construction or renovation.

Linear: this is a specific type of connection bridge, often several metres long, which can account for a significant share of a building's overall losses.

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How to detect a thermal insulation issue?

Certain signs can alert you:

• A feeling of cold near the walls.
• Temperature differences between the walls.
• Condensation on windows or ceilings.
• Mould, often a sign of a thermal bridge.
• High energy bills.

Visual inspection:

Carefully examine the typical zones for thermal bridges, such as wall/floor/ceiling junctions, window frames and pipe penetrations through walls.

Infrared thermography

For a precise diagnosis, an infrared thermography carried out by a professional is the most reliable method.

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Solutions to correct thermal bridges

There are several methods for correcting thermal bridges:

External insulation (ITE):

• Principle: wraps the building in a continuous layer of insulation.
• Advantages: effective at eliminating thermal bridges.
• Disadvantages: high cost, change to the external appearance.

Internal insulation (ITI):

• Principle: lays a layer of insulation on the inside of the walls.
• Advantages: financially accessible, easy to carry out.
• Disadvantages: less effective, reduces living space.

Thermal break components:

• Principle: elements made of insulating materials inserted at the junction.
• Advantages: targeted at specific singular points.
• Disadvantages: limited effectiveness if poorly installed.

Sealing (caulking):

• Principle: fills cracks around windows and doors.
• Advantages: simple and inexpensive.
• Disadvantages: does not address structural thermal bridges.

Insulation injection:

• Principle: injects insulation into hollow walls.
• Advantages: minimally invasive, improves insulation.
• Disadvantages: variable effectiveness depending on the type of insulation.

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The benefits of treating thermal bridges

Treating thermal bridges is a profitable investment:

• Reduction of energy bills.
• Greater thermal comfort.
• Enhanced property value.
• Prevention of damp and mould.

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EDIREX: your partner to limit heat loss

Have you identified thermal bridges in your home? Make an appointment online and benefit from expert advice to improve your home's thermal performance.