What Are the Requirements for the Substrate Wall When Installing UHPC Exterior Wall Panels?

UHPC exterior wall panels use a dry-hanging curtain wall system, whose requirements for the base wall differ fundamentally from traditional wet-adhered materials. The core is to provide a safe, reliable load-bearing foundation for the "support framing system", rather than a flat surface for direct adhesion. The base requirements can be summarized as "sufficient strength, overall stability, accurate positioning, and corrosion-resistant durability". Across numerous projects, whether concrete shear walls, masonry infill walls, or steel structures, Qinglong Group has developed mature base assessment and treatment solutions. In the Ouargla Hotel project in Algeria, we faced a complex mixed base of masonry and concrete, and successfully completed the UHPC curtain wall installation through targeted reinforcement and transfer layer design.

Base Strength and Load-Bearing Capacity Are Fundamental

The base wall (or structural beams and columns) must be able to withstand the curtain wall loads transmitted through embedded parts or post-installed anchors (including dead weight, wind loads, and seismic action). Concrete base strength should generally not be lower than C25, and pull-out testing is required to verify its actual bond strength. For masonry (brick, block) infill walls, due to their low strength and poor integrity, anchoring framing directly to the masonry is strictly prohibited. A "structural transfer layer" must be established, i.e., loads are transferred to the surrounding concrete beams, columns, or ring beams through chemical anchors or through-wall bolts. Qinglong performs load calculations at the detailed design stage to define the load requirements for each anchorage point.

Base Flatness and Verticality Affect Framing Adjustment

Although the dry-hanging system allows three-dimensional adjustment through framing and hangers (typically ≥20mm in each direction), excessive unevenness in the base consumes too much adjustment allowance and may lead to unnecessary enlargement of framing sections. Qinglong requires that the flatness deviation of concrete bases should not exceed 10mm/2m. Before construction, we use a 3D laser scanner to take actual measurements of the base and generate deviation cloud maps, then adjust the framing layout or perform local chiseling and repair accordingly, ensuring the framing installation surface falls within an adjustable range.

Base Durability and Waterproofing/Moisture Protection

The base wall itself should possess basic durability and waterproof performance to prevent internal damage from affecting the curtain wall system. For masonry infill walls prone to water seepage, exterior wall waterproofing should be completed before framing installation. In humid regions, the base surface should not have prolonged standing water or severe efflorescence. All drilled holes for post-installed anchors should be sealed after installation to prevent water seepage paths. Qinglong inspects the integrity of the base waterproofing layer and provides repair recommendations.

Embedded Part Precision and Anti-Corrosion Treatment

If embedded parts are used, their positional deviation directly affects framing installation. Qinglong requires that during main structure construction, the positional deviation of embedded parts should not exceed 20mm, and the elevation deviation should not exceed 10mm. For post-installed anchors, on-site pull-out force testing must be conducted in accordance with standards. All metal components connected to the base (such as post-installed steel plates) require anti-corrosion treatment. Scientific base assessment and treatment is the cornerstone of a safe and long-lasting UHPC curtain wall system.