Curtain Wall Facades in Kerman: Mullion and Face-Cap Design

How Does a Mullion-and-Transom Face-Cap Curtain Wall Work?

A curtain wall is a non-loadbearing envelope that transfers its self-weight, glass weight, and facade pressures to the primary structure through vertical and horizontal members. It does not carry floor loads, but it must respond predictably to wind pressure and suction, temperature change, component weight, and permitted building movement. Grid appearance and sightline width alone are not a design basis.

Vertical mullions provide the main path for wind loads to the anchors; horizontal transoms receive glass weight and transfer it to the mullions. Section depth and geometry, grid spacing, storey height, anchor spacing, and glazing specification affect stress and deflection. Selecting a profile series without checking the project grid can cause excessive movement, glass stress, or failed weather seals.

In a face-cap system, an external pressure plate and cover cap retain the glass against the grid. Caps may be visible in both directions or arranged in horizontal and vertical combinations. Whatever the appearance, the pressure plate, screws, gaskets, and drainage must retain their system function. Screw spacing and continuous gasket contact must follow the system requirements and panel dimensions.

Many stick curtain wall systems drain water that passes the outer layer through pressure-equalized chambers and weep paths, rather than relying on a single seal. Blocked slots, poor transom joints, or interrupted drainage can cause water accumulation and ingress. Section details and connections therefore matter more to performance than the cap’s finished appearance.

Mullion Engineering, Glazing Selection & Structural Connections

Grid Layout and Wind Loads

Wind pressure is not uniform across a facade. Building height, location and form, corner and edge zones, and nearby obstructions affect pressure and suction. The grid must be checked against project design data. Closer mullion spacing, deeper sections, or different anchor positions can change capacity, but each decision must remain coordinated with the architecture, glass sizes, and installation route.

Verification is not limited to allowable stress. Mullion deflection affects joints, glass, sightlines, and weather sealing. A member may have adequate strength yet deflect too much for the panel size or connection detail. Project criteria and system limits must be recorded before the grid is finalized.

Glass, Spacers & Safe Edges

Facade glass is selected for panel dimensions, wind load, post-breakage safety, thermal control, and appearance. Tempered, laminated, or double-glazed configurations depend on location and project requirements. Glass weight affects transoms, setting blocks, connections, and handling. For a DGU, unit quality, spacer, secondary seal, and material compatibility with facade exposure are critical.

Glass edges must not contact metal or screws directly. Setting blocks transfer weight to the intended points and maintain clearance. Labels such as ‘tempered’ or ‘double glazed’ are incomplete specifications: each pane thickness, treatment, colour, coating, installation orientation, and edge requirement must be listed in the glass schedule.

Anchors, Brackets & Construction Tolerances

Curtain wall connections must transfer forces to suitable structural members while allowing adjustment for actual building tolerances. Fixing an adequate mullion to a weak or uncertain substrate leaves the load path incomplete. Shop drawings must define bracket type and spacing, screws or anchors, plate thickness, and weld or mechanical-connection quality.

The built structure rarely matches ideal drawing grids exactly. As-built surveys, slab-edge checks, and a defined adjustment range prevent rework. Slotted holes and sliding details must permit the intended movement without weakening the connection against its primary force.

Curtain Wall Design, Fabrication & Installation in Kerman

The process begins with architectural and structural drawings, facade dimensions, floor levels, slab-edge details, and performance requirements. A 3D model or elevations clarify geometry, but fabrication requires setting-out grids, sections, connection details, and a glass schedule. For an existing or completed structure, an as-built survey must feed actual deviations into the shop drawings.

The initial grid follows architectural lines, practical glass fabrication and handling sizes, opening locations, and load paths. Mullions, transoms, anchors, and glass make-up are then checked. Moving one gridline can change panel weight, profile capacity, and facade appearance together, so architectural and engineering coordination must be complete before materials are ordered.

Shop drawings must identify each member, cut length, machining location, joint type, sealing components, and assembly sequence. Each glass panel also needs a code, dimensions, make-up, colour, treatment, and installation position. This coding enables the factory, logistics team, and installers to distinguish similar-looking components and place them correctly.

Fabrication includes profile cutting and drilling, preparation of transom joints, installation of reinforcement, and finish inspection. Swarf, sealant, or incorrect assembly must not obstruct drainage paths. Before dispatch, lengths, machining positions, and component codes are checked against the production list.

Installation normally starts by verifying grids and fitting brackets. Mullions are aligned and anchored, transoms and horizontal components are added, and the grid is checked for level, plumb, and opening dimensions. Glazing before the grid is fully fixed and verified can make later correction difficult.

After glass and pressure plates are installed, gaskets, cover caps, and perimeter joints are completed. Corners, intersections, and interfaces with roofs, parapets, floors, and adjoining facades are critical. Perimeter seals must accommodate relative movement and be compatible with both substrates and sealant. Excess sealant cannot replace a properly detailed drainage path.

At handover, sightlines, glass condition, opening operation, gasket continuity, caps, and perimeter joints are inspected. On sensitive projects, an agreed local water test can be completed before access equipment is removed. Photographs and inspection records of concealed details are valuable for future maintenance.

For a system overview, see the curtain wall section on the services page . The article What Is a Curtain Wall and Where Is It Used? also explains the system’s basic definition, components, and applications. The Kerman Mall project shows how the facade grid relates to the project architecture.

What Affects the Cost of a Curtain Wall Facade?

Facade cost cannot be derived from one fixed area rate. Building height and geometry, design wind pressure, grid spacing, mullion series and depth, face-cap configuration, profile colour and finish, glass make-up and size, openings, anchors and substrate, installation access, scaffolding or handling equipment, and perimeter complexity all matter. Facades of similar area may require very different fabrication and installation because of panel sizes or corner quantities.

Quotations are comparable only when their scope is the same. Surveying, calculations, shop drawings, profiles, reinforcement, brackets and anchors, glass, gaskets, caps, perimeter sealing, transport, access equipment, installation, and agreed testing must be stated in writing. An omitted item may lower the initial figure but become a separate cost or responsibility during construction.

Reducing mullion depth or increasing panel size is not simply a cost decision; capacity and deflection must be verified. Heavier glass also affects profiles, setting blocks, transport, and installation. Genuine optimization considers the architectural grid, manufacturable sizes, cutting waste, and repeated types together instead of choosing one cheaper component in isolation.

For an initial estimate, submit elevations, architectural sections, building height, project location, approximate grid dimensions, and the intended glass specification. We will identify the information needed for a technical proposal and site visit. Send project details through the contact and consultation page ; the Behinwin home page also links to the factory, projects, and other services.