Curtain wall, storefront and window wall describe different approaches to glazed enclosure. Their support, movement, drainage, thermal and installation details matter more than how similar they look from the street. Select a complete system for the building’s loads and interfaces, then coordinate structure, enclosure, fire protection, glazing and maintenance through project-specific design.
Canadian planning context. Technical examples from other regions are identified in the guide; approval and performance requirements must be checked for the actual building and jurisdiction. Original explanatory diagrams are not construction details.
- A glazed façade carries its own weight and environmental loads even when it does not support building floors.
- A system name does not establish a universal height limit or performance level.
- Anchors, slab edges, perimeter joints and drainage need coordinated details.
- Vision glass, spandrels, vents and entrances have different roles within one façade.
- Mock-ups and field testing need written acceptance criteria tied to the actual project.
01 /Start with the load path and building interface
A commercial glass façade is an engineered enclosure, not a collection of oversized residential windows. It must transfer its own weight, wind and other applicable actions to suitable building supports while managing weather, heat, air and movement. The key distinction is how each proposed system connects to the structure and adjacent construction. A similar grid of aluminium and glass can conceal very different support and drainage arrangements.
Kawneer’s curtain-wall overview distinguishes field-assembled stick systems and shop-assembled unitized systems. Its architectural manuals also separate storefront framing, windows and curtain-wall product families. These are manufacturer examples, not a rule that every product in a named family suits every building or exposure.
Ask the façade designer to describe the selected system with sections at the head, sill, jamb, intermediate floor and corner. An elevation establishes appearance; a section reveals support, seals, cavities and thermal continuity. The design team should identify the applicable Canadian regulatory and structural requirements rather than accepting a familiar U.S. product specification unchanged.
02 /Use the terms carefully
| Term | Typical arrangement | Question the drawing must answer |
|---|---|---|
| Curtain wall | An exterior enclosure attached to the structural building, often continuing past floor edges | How do anchors, movement joints and floor-edge interfaces work? |
| Window wall | Glazed units or framing within a floor-to-floor opening | How are slab-edge closures and each perimeter sealed and insulated? |
| Storefront | Framed glazing commonly coordinated with entrances and individual openings | Does this product meet the project’s span, drainage and exposure requirements? |
| Punched window | A window within a surrounding wall opening | How does the perimeter connect to the wall’s control layers? |
These descriptions help identify questions; they do not supply universal dimensions or height limits. Manufacturers may use overlapping names, and a specialised storefront system can differ greatly from a basic one. Avoid choosing a product solely because a previous project called a similar-looking assembly “curtain wall.”
Establish whether the work is new construction, a complete façade renewal or local glass replacement. Replacing an insulating glass unit within a retained façade is a different scope from changing framing and anchors. A local repair can preserve most of the building enclosure, but it cannot automatically correct obsolete thermal details or systemic water leakage.
03 /Coordinate structure, movement and attachments
The enclosure and building structure move. Thermal expansion, floor deflection, construction tolerance, drift and other project-specific actions must be allowed for in the system. A connection that looks sturdy may still restrain movement incorrectly or transfer a load to a component not designed to carry it. The engineer should define the load path, connection design and movement allowances.
Keep structural attachment distinct from cosmetic trim. Cover caps, closure pieces and sealant are not substitutes for suitable anchors and substrate. Verify where the anchor meets concrete, steel or another structural support and who is responsible for that interface. Existing anchors may require investigation before a façade is retained or re-glazed.
A project with different contractors for structure, curtain wall and interior fit-out needs one coordinated interface drawing. Identify which dimensions are design assumptions and which must be field verified. Changes to slab edges, supports or glazing weights should return to the responsible designer rather than being absorbed as an undocumented installation adjustment.
04 /Follow water through the actual cavities
Commercial glazing details may use gaskets, sealed joints, internal drainage and pressure-management cavities in different combinations. Review how water that reaches a glazing pocket or frame cavity is directed outward. A neat exterior seal is only one visible element. Internal continuity at intersections, splices, ends and corners can be equally important.
Use the selected system’s architectural details and manuals to trace each cavity and connection. A manufacturer’s reference drawing is not a ready-to-build solution for every wall, climate or opening. The project’s approved shop drawings should identify how the standard product detail connects to the actual structure and enclosure.
Do not retrofit drain holes, seal a cavity or bridge an expansion joint without a reviewed repair detail. A water stain inside can originate above or beside the visible wet location. Investigation may need staged opening-up and controlled testing. Record weather, wind direction and affected elevations before deciding that every pane seal has failed.
05 /Thermal bridges and condensation are façade-wide issues
A glazed façade contains frames, glass edges, anchors, closures and spandrel zones as well as the vision glass. Centre-of-glass performance alone cannot describe the assembly. Ask for the relevant whole-system thermal assessment, the assumed dimensions and the interfaces included. A thermally improved mullion does not automatically eliminate heat flow at a poorly detailed slab-edge closure.
Indoor humidity, outdoor conditions and local surface temperatures determine where condensation can occur. Corners, frame intersections and spandrel back pans may behave differently from the central pane. High interior moisture can reveal a cold bridge that was less visible under previous occupancy conditions. The design brief should state the intended indoor conditions and identify the required analysis.
Solar gain and daylight also belong in the façade design. Glass tint, coatings, frit, shading and interior layout affect glare and cooling demand. Select appearance samples under realistic viewing conditions. A beautiful rendering may conceal reflective colour shifts, visible spandrel mismatch or uncomfortable sunlight at occupied desks.
06 /Vision glass, spandrels, vents and doors are not interchangeable
Vision glazing is intended for view and daylight. Spandrel areas conceal opaque construction and may include insulated back pans and other components. Their thermal and moisture details differ. A visually matching piece of glass does not establish that a spandrel assembly is suitable or that an opaque closure can be omitted.
Operable vents and entrances introduce their own hinges, hardware, seals, access requirements and performance limits. A façade specification should identify which units operate, who uses them and how they are serviced. The appearance of a continuous grid should not hide the fact that one opening has a different glass build-up or a different load condition.
Fire and smoke interfaces need project-specific design. At floor edges or rated boundaries, the required perimeter fire-containment or closure system is not ordinary weather caulking. Obtain the appropriate tested or approved system and have the responsible professionals coordinate it with movement, anchors and finishes. Do not infer a fire rating from tempered or laminated vision glass.
07 /Turn mock-ups and testing into decisions
An appearance mock-up helps review sightlines, finishes, glass, joints and workmanship. A performance mock-up or field test addresses specified behaviours under stated conditions. They answer different questions. Define the purpose, specimen, installation, test standard, pressure or other parameters, observers and acceptance criteria before ordering the mock-up.
Include representative difficult interfaces: a corner, operable vent, door, spandrel transition or slab-edge closure where relevant. A simple middle-of-wall specimen may not expose the details most likely to cause trouble. Establish who corrects a failed result, how a revised detail is approved and whether testing is repeated.
Retain the accepted specimen or photographic and drawing record. Field changes should be compared against that baseline. Passing one test does not certify every opening or all future weather conditions; record its scope honestly. Use inspection and quality-control hold points during fabrication and installation to keep the production work aligned with the accepted design.
08 /Design maintenance and future glass replacement now
Ask which side provides glazing access, what must be removed and how a damaged pane will be lifted and transported. Interior furniture, ceilings, exterior landscaping and access equipment can affect future service. A system that can be installed during construction may be difficult to re-glaze once the building is occupied.
Keep a façade asset record containing system identifiers, glass make-ups, finish codes, approved drawings, gasket and sealant specifications, test reports and maintenance requirements. Product changes and local repairs should be recorded by location. Without that archive, a replacement pane may have a different appearance or an incompatible support detail.
For a condominium or commercial owner, separate immediate make-safe work from a façade renewal plan. Clarify responsibility, access, occupant notices and investigation scope with the appropriate professionals and property governance. A comprehensive façade project needs an enclosure team, structural coordination and documented procurement; it cannot be reduced to a residential window price per opening.
FAQQuestions people ask
Can storefront be used on any building if the glass fits?
No. The specific system must meet the project’s support, span, movement, air, water, thermal and other requirements. A product family name is not a universal suitability statement.
Does curtain wall support the building floors?
It is generally an enclosure rather than the floor-supporting structure, but it still transfers its own weight and environmental loads to designed supports. The project’s engineer defines the load path.
Is a fire-rated floor edge sealed with ordinary window caulk?
No. Required fire and smoke interfaces need an appropriate designed system coordinated with the façade, structure, movement and local requirements.