Storefront and curtain wall can look alike on an elevation, since both are aluminum-framed glass systems. In the takeoff they behave very differently. They attach to the building in different ways, they are engineered and tested differently, and they bring different equipment, lead times and scope gaps. Getting the storefront vs curtain wall call wrong at estimate stage can move a glazing price a long way. This post explains the differences that matter and shows what to measure for each.
It is written for contractors and estimators pricing glazing from drawings. If you want a complete glazing takeoff prepared for you, see our glass and glazing estimation service.
How the two systems differ
Storefront is a lighter framing system normally installed within a single story. It sits in an opening, often between the floor and the structure above, and the frame is relatively shallow. Water that gets into the system generally drains out at the sill of the whole run. It is not designed to absorb large movements between floors.
Curtain wall is a heavier, deeper framing system that hangs from the building structure, usually at the slab edges, and can span multiple stories. It is designed to accommodate floor-to-floor movement, wind loads and thermal movement. Each lite is typically drained individually, and the system is engineered for the specific project. Curtain wall is built either as a stick system, assembled piece by piece on site, or as a unitized system, with factory-assembled panels hoisted into place.
There is also window wall, installed between floor slabs rather than hung from them. Industry definitions of it are not uniform, so confirm with the specification which system is meant. A useful overview of the first two is available from Building Enclosure.
Where each one is specified
In MasterFormat, aluminum-framed entrances and storefronts fall under 08 41 13, and glazed aluminum curtain walls under 08 44 13. Reading the right section tells you the performance requirements, testing, finishes and glass types, and whether shop drawings and engineering are required. Do not assume a system from the drawings alone. A mullion grid on an elevation does not tell you whether the architect wants a storefront or a curtain wall.
What to measure for storefront
- Linear feet of vertical and horizontal framing members, counted by elevation and type, including head, sill and jambs.
- Number of glass lites by size and type, and square feet of glass by type.
- Entrance doors, frames, hardware and closers, counted as units, with the door and frame schedule as a cross-check.
- Finish: anodized or painted, by color and by surface area.
- Sealants, gaskets, setting blocks, flashing and anchors.
- Labor and access: scaffold, lift or ladder work, and glazing crew size.
What to measure for curtain wall
- Linear feet of mullions by type, and the number of unitized panels or stick modules.
- Vision glass, spandrel glass and opaque panels, separated by type and area, with the glass makeup such as insulated units, low-E coatings, and tempered or laminated glass.
- Anchors, brackets and embeds, and who supplies them if they are cast into concrete or fixed to steel.
- Insulation and backpans behind spandrel areas.
- Slab-edge firestopping and smoke seals between floors, which may belong to another trade.
- Flashing, sealants and perimeter joints at head, sill and jambs.
- Engineering, shop drawings, mock-ups and performance testing.
- Access and hoisting: swing stages, lifts, cranes or hoists, and the sequence they impose on the schedule.
A quick storefront example
These figures are illustrative. A storefront run is 40 feet wide and 10 feet high, divided into eight 5-foot bays with a transom line at 7 feet.
- Lower lites: 5 ft × 7 ft = 35 sq ft each × 8 = 280 sq ft.
- Transom lites: 5 ft × 3 ft = 15 sq ft each × 8 = 120 sq ft.
- Total: 400 sq ft, which matches 40 × 10 and confirms the grid before frame deductions.
- Vertical members: 9 (eight bays plus one) × 10 ft = 90 linear feet.
- Horizontal members: head 40 ft + sill 40 ft + transom rail 40 ft = 120 linear feet.
- Framing total: 210 linear feet.
In practice you would deduct the frame depth from each lite and add doors, hardware and finishes. But checking the grid this way catches counting errors before they reach the price.
Scope gaps to catch
Glazing touches many trades, and most disputes sit at the edges. Ask who owns:
- The air and water barrier transition between the wall and the frame, discussed in our guide to building envelope estimating.
- Slab-edge firestopping behind curtain wall.
- Embeds, steel supports and blocking that anchor the system.
- Head and sill flashing, interior trim and drywall returns.
- Entrance door hardware, electric strikes, access control and automatic operators, which may be shared between the openings and electrical scopes. Our openings estimation service covers doors and hardware from the schedules.
Lead times and procurement
Curtain wall systems and special glass often have long lead times and need approved shop drawings before fabrication. Delays here can hold up the building enclosure and everything behind it. Allow for this in the schedule and in any escalation allowance. Our post on long-lead procurement planning explains how to handle it.
Common glazing takeoff mistakes
- Treating curtain wall like a larger storefront and using the same unit rates.
- Pricing glass by gross opening area and forgetting frame deductions or the difference between vision and spandrel glass.
- Leaving out access equipment, shop drawings, mock-ups and testing.
- Missing slab-edge firestopping and perimeter sealants.
- Using a single finish price for every frame color and coating.
- Not checking the door and hardware schedule against the elevation.
More on how errors like these affect a bid is in our list of common estimating mistakes.
Frequently asked questions
Can storefront be used on multiple stories?
Storefront is normally designed for a single story and a limited height. Taller or multi-story applications generally call for curtain wall or window wall. Always check the manufacturer’s tested limits and the specification.
Is curtain wall always more expensive than storefront?
Per square foot, curtain wall usually costs more because of heavier framing, engineering, testing and installation methods. The right comparison also includes performance requirements, height and schedule, so the system is chosen by what the project needs.
What is the difference between stick and unitized curtain wall?
Stick systems are assembled on site, piece by piece. Unitized systems are factory-assembled panels installed as units, which can speed up site work but raises shop drawing and lead-time requirements.
Should glass be a separate line in the estimate?
Yes. Glass type, coating and thickness vary so much that glass should be priced separately from framing, with vision, spandrel and special glass shown on their own lines.
Get a glazing takeoff by system
We prepare glazing takeoffs that separate storefront, curtain wall, glass, doors and accessories, so you can price each against current supplier quotes. See our glass and glazing estimation service, the wider services by trade, or our commercial cost estimating guide.