The key to preventing thermal bridging in building exterior wall insulation lies in the dual effects of its material properties and structural design. As a Class A non-combustible fire-resistant insulation material made primarily of basalt, rock wool board possesses an extremely low thermal conductivity, effectively blocking heat transfer paths and weakening the physical basis for thermal bridging at the material level. Its inorganic fiber structure not only withstands high temperatures but also maintains stable performance under complex climatic conditions, avoiding the potential for thermal bridging caused by material deformation or aging.
The structural design of the external insulation system is the core advantage of rock wool board in preventing thermal bridging. Traditional internal insulation structures, due to the insulation layer being segmented by the wall, struggle to achieve continuous coverage at junctions between internal and external walls, and between floor slabs and walls, creating dense heat flow channels. In contrast, the external insulation system using rock wool board completely wraps the insulation layer around the building's exterior, eliminating uneven heat conduction in critical areas such as structural beams, columns, and window/door openings through a continuous, uninterrupted installation. For example, at the junction of window frames and walls, rock wool board can extend to cover the outside of the window frame, forming a continuous whole with the insulation layer, preventing sudden drops in localized temperature caused by the window frame's metal material having a much higher thermal conductivity than the wall.
The construction process of rock wool board is crucial for thermal bridging. During construction, a special bonding mortar must be used to firmly adhere the rock wool board to the base wall, and it must be further secured with anchors to ensure a seamless connection between the insulation layer and the wall. For the joints between the boards, caulking material must be used to fill the joints and alkali-resistant fiberglass mesh must be pressed in to form an elastic sealing layer, preventing the degradation of thermal performance caused by rainwater and air infiltration. For protruding components such as eaves and parapet walls, the rock wool board must extend to cover the outside of the component and be secured with thermal break anchors to prevent thermal bridges from forming at metal connectors.
For weak points in the building structure, rock wool board can be used in composite construction to strengthen thermal bridging control. For example, in concrete structural columns, rock wool sandwich panels with steel wire mesh can be used. The metal mesh flexibly connects the rock wool layer to the structural layer, ensuring insulation continuity while avoiding thermal bridging caused by rigid connections. At the junction of basement exterior walls and foundations, rock wool board can be used in combination with waterproof membranes to form an integrated insulation and waterproofing system, eliminating thermal bridging caused by interruptions in the insulation layer.
The fire resistance of rock wool board synergistically enhances its thermal bridging control. As a Class A non-combustible material, rock wool board will not burn or release toxic gases in a fire. Its high-temperature stability ensures the insulation layer remains intact under extreme conditions, preventing the expansion of thermal bridging due to material failure. This characteristic makes it particularly suitable for high-rise buildings and locations with stringent fire safety requirements, meeting energy-saving needs while improving overall building safety.
Environmental adaptability is another advantage of rock wool board in preventing thermal bridging. Its temperature resistance range covers -240℃ to 650℃, coping with thermal expansion and contraction under extreme climatic conditions and preventing insulation layer cracking due to material deformation. Meanwhile, rock wool board boasts a water-repellent rate exceeding 95%, effectively preventing rainwater penetration and avoiding an increase in thermal conductivity due to moisture absorption in the insulation layer, thus ensuring stable long-term thermal performance.
In terms of system compatibility, rock wool board can be used with a variety of exterior wall finishes. Whether it's paint, facing brick, or curtain wall systems, rock wool board can meet the energy-saving requirements of different projects by adjusting the thickness of the structural layer and the fixing method. Its lightweight characteristics (density 60-200 kg/m³) facilitate construction and installation, while its high compressive and tensile strength ensures that the insulation layer is not easily deformed during long-term use, maintaining the durability of thermal bridging control. Through multiple guarantees of material performance, structural design, construction technology, and system synergy, rock wool board provides a comprehensive and reliable solution for building exterior wall insulation.
