Window wall vs curtain wall is primarily a comparison of facade arrangement and building interfaces. Window wall commonly fits glazing between floor slabs, while curtain wall commonly passes outside slab edges as an exterior wall system. Actual proprietary systems differ. A procurement decision should begin with plans and sections showing what each system connects to and which party designs those connections.

Follow the slab edge through the section

For a window-wall proposal, identify the head, sill and slab-edge treatment at each floor. Establish how the system connects to the wall’s air and water control layers and how the slab edge is finished. A neat interior elevation can conceal a complicated external junction.

For curtain wall, show the supporting brackets, anchors and interfaces with adjacent construction. Determine where the system transfers loads and how installation tolerances are accommodated. The project engineer must verify the structural scheme; generic system descriptions do not replace project-specific design.

Coordinate movement and weather management

The facade must accommodate the building’s anticipated movements and construction tolerances. Ask the designer to identify the movement assumptions and show which joints accommodate them. Avoid resolving a dimensional conflict by removing a designed joint or forcing a frame into an undersized opening.

Water drainage, air seals and thermal continuity should be traceable through the details. Identify how horizontal and vertical junctions connect, particularly at corners, terraces and transitions to other cladding. The Whole Building Design Guide’s moisture-management guidance is a useful reminder that window and door penetrations and construction joints deserve coordinated attention.

Define procurement boundaries before comparing prices

Ask each bidder to list included framing, glass, anchors, perimeter seals, slab-edge covers and installation work. Clarify responsibility for structural calculations, shop drawings, mock-ups and performance testing where specified. A square-metre price is incomplete if one proposal excludes major interfaces.

Also confirm whether the proposal is a factory-assembled unitized system or a site-assembled arrangement. Delivery sequence, storage space, lifting access and installation labour may differ. Do not assume the words window wall and curtain wall alone determine the assembly method.

Use a coordinated drawing checklist

• Plans, elevations and typical head, sill and jamb sections.
• Slab-edge and adjoining-cladding details.
• Loads, movements, tolerances and anchor substrates.
• Glass build-up, opening panels and maintenance access.
• Clear design, supply, installation and inspection responsibilities.

Compare Shanghai Slang window wall options and curtain wall options within architectural products. Send the project sections and scope boundaries with the enquiry. The useful comparison is between complete facade proposals for the same building, including interfaces and delivery strategy, rather than between two product names.