What Is the Connection Solution Between UHPC Exterior Walls and Door/Window Openings? The Art of Joints and Qinglong Group's Refined Edge-Finishing System

The junction between UHPC exterior walls and door and window openings is the "last hundred meters" of waterproofing, airtightness, and aesthetics in a curtain wall system, and must adopt a comprehensive approach of "structural waterproofing as primary, material sealing as secondary, multiple lines of defense, and systematic treatment". Qinglong Group has developed a standardized library of joint details for different door and window systems (such as aluminum windows, curtain wall windows, and entrance doors) and UHPC installation methods (dry-hanging and adhesive bonding): core measures include setting rabbets or flashing boards to achieve structural water drainage, applying multiple sealant lines (weatherproof sealant + structural sealant) to form airtight and watertight defense lines, and ensuring thermal expansion compatibility between UHPC and door/window frames. In the Shenzhen Yirui Biotechnology Building project, we achieved millimeter-level finishing precision and excellent waterproofing performance through the precise "overlapping" connection between UHPC window surrounds and unitized curtain wall windows, which has withstood multiple typhoons and rainstorms. Refined finishing is the hallmark of quality engineering.

"Structural Waterproofing" Is the First Line of Defense

At the top of the opening, the UHPC panel or trim is designed as an outward-sloping "flashing board"; on both sides and at the bottom, inward-recessed "rabbets" are set. Using the principle of gravity, most rainwater is diverted away before it reaches the sealant joints, greatly reducing the waterproofing pressure on the joints. This is the most reliable and durable waterproofing measure.

"Multiple Sealing Lines" Form the Core Barrier

Between the UHPC and the door/window frame, two sealing lines are installed: on the exterior side, silicone weatherproof sealant with excellent weather resistance is applied, mainly for waterproofing and UV resistance; on the interior side (inside the wall or within the cavity), a more elastic sealant or gasket may be used, mainly for airtightness. A pressure-equalized cavity is formed between the two seals, further improving water tightness.

Connection Design That Accommodates Movement

UHPC and metal door/window frames have different thermal expansion coefficients, so space must be reserved for relative movement between the two. Connections should not be fully rigidly fixed; slotted-hole screw connections or elastic spacer blocks can be used. The sealant width must be calculated to ensure it can absorb the expected maximum deformation without failure.

Insulation Continuity and Cold Bridge Prevention

In buildings with high energy-efficiency requirements, the insulation layer around the opening must be continuous and free of breaks. UHPC window surrounds or finishing trims can adopt thermal-bridge-breaking designs or be integrated with the insulation layer, preventing this area from becoming a weak point for heat loss and condensation.

Opening junction treatment tests a manufacturer's detailed design capability and mastery of details. Qinglong Group has extensive experience in joint treatment and a complete set of standard construction detail drawings, ensuring that every opening becomes an integral part of the building that is safe, energy-efficient, and aesthetically pleasing.