Have you ever had this problem: even with high-quality insulation materials, the building still feels "leaky" in winter, mold spots mysteriously appear in the corners, and even the heating cost is high? Or in the hot summer, the air conditioner is working hard, but the indoor temperature is still difficult to reach the ideal cool?
If the answer is yes, then your building is likely being harassed by an invisible assassin-it is the cold bridge.
As a company specializing in the research and application of high-performance silicone foam materials, we are well aware that thermal bridges remain a persistent challenge in modern building energy efficiency and durability. Today, let us unveil the mystery of thermal bridges and explore fundamental solutions to address this issue.
1. What is a cold bridge? It's like a hole in a building's insulation.
Imagine this: during a freezing winter, you're wearing a thick down jacket with a poorly zipped or torn opening. The piercing cold wind would rush through this gap, instantly making you shiver. This' gap 'is your body's 'cold bridge'.
In architectural physics, a thermal bridge refers to a weak link in a building envelope where insulation performance is significantly lower than other areas. These weak points act like 'bridges,' creating a 'fast track' for heat transfer between the interior and exterior.
Cold bridges are mainly divided into 3 categories:
Category 1: Structural cold bridge
This is the most common and important type, caused by the difference in thermal conductivity of different materials in the building.
Cause: In the main structure such as reinforced concrete and brick concrete, the thermal conductivity of embedded metal components, concrete beams, columns, floors and other materials is much higher than the insulation materials filled in the wall.
Image metaphor: It's like sewing a few metal bars into a cotton coat, and the heat escapes quickly along those bars.
typical example ：
Penetration of exterior walls by reinforced concrete beams/columns: This is the most classic example of the connection between the beams and columns of a frame structure and the exterior wall infill wall.
Connection between exterior wall and floor/ interior wall:
Overhanging concrete floors, balcony slabs, and canopies: These components are directly exposed to the outdoors and can become a huge cold bridge if they are not insulated.
Metal components in the building: such as the connection parts of steel structure, embedded parts, etc.
Second type: structural cold bridge
This kind of cold bridge is formed because of the change of building geometry, which leads to the increase of local heat flux density.
Cause: In the corner of the building, eaves, window holes and other parts, the heat transfer area is greater than the heat dissipation area, resulting in the heat in these corners and concentrated outward transmission.
Image metaphor: Like a cube of ice, its edges always melt faster than the plane because they are exposed in multiple directions at the same time.
typical example ：
Exterior wall angles: The protruding corners (yang angles) and recessed corners (yin angles) of a building.
Parapet wall, eave root:
Around door and window openings: Although there are material differences here, the abrupt change in geometry is an important factor in the formation of cold bridges.
Third type: repetitive cold bridge
This type of cold bridge is caused by the insulation layer being periodically and repeatedly interrupted.
Cause: Anchors (such as bolts and brackets) used to fix the insulation layer or decorative panel of the outer wall will penetrate the insulation layer and form a regular heat conduction path.
Image metaphor: It is like using many nails to nail a cotton coat to a wooden board, each nail is a small cold point.
typical example ：
Fixed anchor bolts for external wall insulation system:
Metal frame and connectors of curtain wall:
Support frame for dry hanging stone/aluminum plate:
2. The Dangers of Cold Bridges: More Than Just 'Cold' – A Chronic Illness for Buildings
The harm of cold bridge is multifaceted, it quietly damages the health of the building and your economic interests:
Energy waste and high costs: Cold bridges are the 'leakage' of energy consumption. In winter, heat is rapidly lost, and in summer, outdoor heat rushes in, resulting in a huge increase in the load of heating and cooling equipment and soaring energy bills. According to statistics, the energy loss caused by cold bridges can account for more than 20% of the total energy consumption of a building.
Condensation and mold growth pose serious health risks: This is the most visible hazard. When warm indoor air meets the cold surface of a thermal bridge, the temperature plummets below the dew point, causing water vapor to condense into droplets. Prolonged dampness creates an ideal breeding ground for mold, which not only damages interior finishes but also triggers respiratory illnesses, severely endangering residents' health.
Building damage and life loss: Continuous condensation will penetrate into the interior of the wall, leading to further deterioration of the wall insulation performance, and even may cause structural safety problems such as steel corrosion, material freeze-thaw damage, etc., greatly shortening the service life of the building.
3.Why are traditional solutions inadequate?
Traditional insulation methods, such as using polystyrene boards (EPS/XPS) and rock wool for exterior insulation, have improved the wall's thermal performance to some extent. However, when dealing with complex joints, irregular structures, or areas requiring higher precision and durability, these materials often prove "clumsy" and "fragile":
Inconvenient cutting and tight fitting: In the beam, column, corner and other irregular parts, the hard insulation board is difficult to cut accurately and fit tightly, easy to leave new gaps and cold bridge.
Compressibility deformation, performance attenuation: under long-term stress or vibration environment, some materials will compress deformation, resulting in the reduction of insulation layer thickness, forming a new cold bridge.
Poor weather resistance and mismatched life span: the anti-aging and fire resistance of some materials is insufficient, and they cannot have the same life span as the main structure of the building.
4. Solution: Using high-performance silicone foam material to dress the building with a "seamless sky suit"
To address the industry's pain point of cold bridges, we propose a solution: high-performance silicone foam insulation material. This isn't just a simple replacement for traditional materials, but a targeted technological upgrade.
Why is silicone foam material a good way to overcome the cold bridge?
Exquisite flexibility and sealing: Like clay, it can bend and compress at will, fitting perfectly to any complex shape and node, achieving "seamless filling" and completely blocking the cold bridge path. Whether it is pipe through the wall, curtain wall connectors or irregular structural interfaces, it can easily cope with it.
Stable long-term performance: Excellent compressive creep resistance, can maintain the original thickness and shape even under long-term pressure, ensure long-term stable insulation performance, eliminate new cold bridge caused by material deformation.
Wide temperature range and excellent fire performance: can maintain elasticity and performance in the extreme environment of-50℃ to 200℃, and itself is inorganic material, reaching the A class fire standard, fundamentally improve the safety level of the building.
Hydrophobic and moisture-proof, one-time and permanent: its closed pore structure makes it have excellent hydrophobicity, can effectively prevent water vapor penetration, eliminate the generation of condensation and mold from the root, and protect the building structure.