1.What is the core difference between color-coated coils and edge-sealed parts?
Color-coated steel coils: Essentially, they are thin steel sheets (substrate) coated with an organic coating. They are a rigid structural material, primarily providing strength, enclosure, and decorative functions.
Curled edge seals: Typically made of flexible elastomers such as rubber, silicone, foam, and plastic. They are functional sealing materials, primarily providing compression resilience, gap filling, and waterproofing/air/dust protection.
2.Why can't color-coated coils perform the sealing function?
Lack of elasticity and resilience: Seals need to deform under pressure to fill uneven surfaces and at least partially spring back after pressure release. Color-coated steel coils (sheet steel) are plastic materials; once bent, they cannot spring back, and deformation is permanent.
Coating easily damaged: If the edges of the color-coated steel coil are repeatedly rolled or compressed, the organic coating on its surface will crack and peel off due to excessive deformation, exposing the metal substrate, leading to rapid corrosion and rust, and complete loss of protective function.
Inability to form a tight seal: The high surface hardness of steel sheets means that even after rolling, the contact with the surface is only hard contact, unable to adapt to minor unevenness, and cannot "fit" gaps like rubber, inevitably resulting in leakage points.
Fatigue and fracture: Under dynamic loads (such as wind vibration and thermal expansion and contraction), repeated bending of the metal leads to metal fatigue, eventually resulting in fracture at the rolled edge.
3.What does the curled edge of a colored roll refer to?
Edge-rolled seals (such as lockstitches): This is a structural connection method. For example, in roof panel installation, the edges of two adjacent panels are rolled together, achieving structural fixation and initial waterproofing through mechanical interlocking. Its waterproofing relies primarily on the design of rainwater flow (slope and overlap) rather than on the material's elastic seal. For higher waterproofing requirements, additional sealing strips or sealant are needed.
True edge-rolled seals: These are independent, elastic strips of material specifically designed to fill the gap between two components.
4.What are the standard practices for achieving sealing in pre-coated roll building systems?
Pre-coated steel coils, used as the main structural/enclosure material, are connected and secured through methods such as edge rolling.
Professional flexible sealing materials are used in conjunction with these materials to provide sealing in critical areas:
Sealing strips: Installed within the grooves of the overlapping pre-coated steel sheets, they achieve a seal upon compression.
Foam backing strips: Fill gaps.
Sealant: Applied to the joints, such as silicone sealant or polyurethane sealant.
Pre-fabricated sealing washers: Used around screws and other penetrating components.
5.If there is a need for sealing, what is the correct approach?
Choose suitable color-coated steel sheets as building panels, and select appropriate rubber/silicone sealing strips or sealants according to the design to solve the problem.