Key Points for Connecting GRC Exterior Walls with Door and Window Openings?

The connection between GRC exterior walls and door/window openings is a critical joint for waterproofing, thermal insulation, and airtightness; improper treatment can easily lead to problems such as leakage and condensation. When handling such joints, Qinglong Group follows the principle of "constructional waterproofing first, material sealing as supplement, and flexible connections to accommodate deformation," ensuring reliable and durable connections through refined design.

Constructional waterproofing design is the first line of defense. The core is to adopt the "rain screen principle" or "pressure-equalized cavity" design. The specific approach is: a gap of a certain width (typically 15-25mm) is reserved between the GRC panel and the door/window frame, with weather-resistant sealant applied on the outer side of the gap as the primary sealing layer. On the inner side of the sealing layer, between the GRC panel and the structural wall, a continuous waterproof breathable membrane is installed and lapped and sealed with the waterproofing layer of the door/window frame, forming a complete second waterproof barrier. More importantly, at the head of the window opening, the GRC panel should be fitted with an effective drip flashing to channel any intruding rainwater to the outside for drainage.

Continuity of insulation and airtightness is key to energy efficiency. The insulation layer of the GRC exterior wall should connect tightly with the insulation on the door/window frame side to avoid breakpoints that form "thermal bridges." On the inner side of the joint, an elastic foamed polyethylene rod should be used as backing, followed by filling with elastic sealant. For buildings with high airtightness requirements, a dedicated airtightness tape should also be used to seal the joints on the interior side, ensuring a continuous and complete airtight layer of the building envelope.

Flexible connections that account for material deformation are essential. GRC, door/window frames (aluminum or uPVC), and the main structure have different coefficients of linear expansion, resulting in varying deformation when temperatures change. Therefore, the connection detail must allow a certain degree of relative displacement. Qinglong typically uses slotted-hole screw connections and reserves sufficient expansion space between the GRC panel and the door/window frame. All sealing materials must have high movement capability (e.g., ±25% or more) to accommodate long-term deformation movement, preventing sealant failure due to excessive stretching or compression.