What Type of Sealant Should Be Used for the Joint Treatment of UHPC Curtain Wall Panels?

The selection of sealant for UHPC curtain wall panel joints must meet four requirements: high elasticity, weather resistance, compatibility, and durability. Silicone sealant (one-component or two-component) is the mainstream choice, with a movement capability of ≥±25% to ensure effective sealing under temperature and wind load effects. In the coastal roofing project of the Hainan International Convention and Exhibition Center, Qinglong Group selected a 25LM-grade (movement capability ±25%) one-component silicone sealant with elongation at break >400% and bond strength to UHPC >0.5MPa. After 10 years in a high-salt-spray, high-UV environment, it still maintains good elasticity and adhesion, with no hardening or cracking. Sealant is the 'soul of waterproofing' for a curtain wall; its performance directly determines the long-term airtightness of the building envelope system.

Silicone Sealant Is the Field-Proven First Choice

Silicone sealant offers excellent weather resistance (stable performance from -40°C to 150°C) and a service life of over 20 years. We prefer well-known brands such as Dow Corning and Sika to ensure material quality. Compatibility and adhesion tests are conducted before installation to prevent adverse reactions.

Joint Design Is the Foundation for Performance

Joint width must be determined by calculation, generally not less than 6mm, with a width-to-depth ratio of 1:1 (e.g., 10mm wide and 10mm deep). We use a process of two-component sealant as the base layer and one-component sealant as the surface layer to ensure dense filling. In the Shenzhen Yirui project, the joint was designed at 12mm, perfectly accommodating ±8mm of temperature-induced movement.

Workmanship Determines the Final Sealing Result

The substrate must be clean and dry; sealant application must be continuous and uniform, formed in a single pass. We train professional sealant teams, certified for the job, to ensure full, smooth joints. Test specimens are set aside every 100 linear meters for tensile adhesion testing.

A high-quality sealing system is the combination of careful design and meticulous workmanship. Qinglong Group strictly controls material selection and installation to ensure the curtain wall remains completely watertight.