Glazing Takeoff Guide: Curtain Wall, Storefront, and Glass Counts

Glazing takeoff turns elevation drawings into square footage of glass, linear feet of aluminum, and counts of IGUs. This guide walks through the difference between curtain wall, storefront, and windows so your next glazing bid catches every opening and gets the glass makeup right.

1. What Glazing Takeoff Covers

A glazing takeoff is the process of pulling every glazed opening on a project into a structured list of quantities. It includes curtain wall, storefront, windows, entrance doors, interior glass, skylights, and often specialty items like glass railings or translucent panels.

What makes glazing takeoff unique

Unlike painting or drywall, glazing is manufactured offsite to exact dimensions. There is no "cut it on site" option. That means your takeoff has to match reality within a fraction of an inch, and shop drawings will be developed from your numbers. A missed opening means an urgent change order and a 6–10 week delay for custom IGUs.

2. Glazing System Types

Curtain wall

Curtain wall is a non-load-bearing exterior glazing system that hangs off the building structure. It spans multiple floors as a unified skin, supports only its own weight plus wind load, and anchors at each floor slab. Typical mullion depth: 6 to 10 inches (sometimes more). Subcategories: stick-built (field-assembled mullion-by-mullion) and unitized (prefab panels craned into place). Unitized is faster on site but more expensive up front.

Storefront

Storefront is a lighter glazing system typically limited to ground-floor heights (around 10–12 feet). Mullion depth is shallower (3–4.5 inches), it is usually shop-fabricated as a pre-engineered system (Kawneer Trifab, YKK YES 45 FS, Vistawall FG), and it installs with flush perimeter framing. Storefront is cheaper per SF than curtain wall but cannot span multiple floors.

Window wall

Window wall is a hybrid — installed between slabs rather than spanning them. Common in mid-rise residential and hotels. Looks like curtain wall from outside but installs floor by floor. Typically less expensive than true curtain wall.

Punched windows

Punched windows are individual openings in a solid wall (brick, precast, metal panel). Measured per unit with frame + IGU. Typical sizes run 3x5, 4x6, 5x7.

Interior glazing

Office partitions, conference room fronts, lobby walls, and frameless shower-style systems. Usually 1/2" tempered glass in aluminum channels or fully frameless systems with clips and top/bottom rails.

3. Drawings You Need

Before starting a glazing quantity takeoff, collect:

• Architectural elevations (exterior and interior).
• Floor plans for plan-view locations of openings.
• Wall sections for head, jamb, and sill details.
• Glazing schedule or window schedule.
• Door schedule for entrance doors.
• Glass type legend linking glass tags to IGU makeup.
• Specifications 08 41 13 (Aluminum-Framed Entrances and Storefronts), 08 44 13 (Glazed Aluminum Curtain Walls), 08 80 00 (Glazing).
• Performance data — wind load (ASCE 7), U-value, SHGC, STC if required.

4. Measuring Elevations

Elevations are your primary tool. Each elevation is a flat view of one face of the building showing glazed area as overlapping rectangles.

Measure by system

Separate your takeoff by system type. Curtain wall has its own line items. Storefront has its own. Punched windows have their own. They all have different prices per SF and different framing per LF. Never lump them together.

Gross vs vision glass

• Gross glazed area: total system area including spandrel panels and transom bands.
• Vision glass: the clear/tinted glass people look through, excluding spandrel.
• Spandrel: the opaque or insulated panel in a curtain wall, typically between floors. Often back-painted glass or metal panel.

Price vision and spandrel separately. Spandrel panels are cheaper per SF than high-performance vision glass.

Elevation measurement process

1. Identify each elevation and its system type(s).
2. Measure overall width × height for gross area.
3. Subtract non-glazed zones (solid wall, metal panel).
4. Count mullions (verticals) and transoms (horizontals) by profile.
5. Map each glass lite to a glass type from the legend.
6. Count entrance doors and frame types.

5. IGUs and Glass Makeup

An IGU (insulating glass unit) is the sealed glass assembly that goes into the framing. Commercial IGUs are typically 1 inch thick total.

Standard commercial IGU makeup

Called out as 1/4" – 1/2" – 1/4": outboard lite, air or argon gap, inboard lite. Total 1 inch. Variations:

• 1/4" – 1/2" argon – 1/4" low-E: thermal-performance standard.
• 1/4" tempered – 1/2" – 1/4" laminated: safety + security glass.
• 1/4" – 1/2" – 1/4" – 1/2" – 1/4": triple-pane (1-3/4" overall), rare but very high performance.

Glass tempering and lamination

• Tempered glass: heat-strengthened, 4–5× stronger than annealed, shatters into small cubes. Required within 18" of floor, in doors, and within 24" of a door.
• Laminated glass: two lites with PVB (polyvinyl butyral) interlayer. Holds together when broken. Required for overhead glazing, security glass, and hurricane zones.
• Heat-soaked tempered: additional process that reduces nickel sulfide inclusion failures. Often spec'd for structural glazing.

Low-E coatings

Low-E (low-emissivity) coatings are thin metallic layers that reflect infrared heat. They are named by manufacturer (Solarban 60, Solarban 70, Solarban 90, LoE 366, LoE 272). The coating position is called out by surface number:

• Surface 1: outside of outboard lite (exterior).
• Surface 2: inside of outboard lite (faces airspace).
• Surface 3: inside of inboard lite (faces airspace).
• Surface 4: inside of inboard lite (interior).

Hot climates typically use surface 2 low-E. Cold climates use surface 3.

6. Mullions and Framing LF

Aluminum framing is measured in linear feet by profile.

Counting framing

For a rectangular curtain wall grid: verticals (mullions) = (length / panel width) + 1. Horizontals (transoms) count at each floor line plus at any mid-bay transom. Multiply each by the height/length to get LF.

Example

A curtain wall 60 ft wide by 24 ft tall (2 floors at 12 ft each) with 6-ft panel width:

• Verticals: (60 / 6) + 1 = 11 mullions × 24 ft = 264 LF.
• Horizontals: 3 transoms (at top, mid, bottom) × 60 ft = 180 LF.
• Total framing: 444 LF before perimeter and splices.

7. Entrance Doors and Hardware

Aluminum entrance doors are part of glazing scope. Take them off from the door schedule.

What to capture per door

• Door size (typically 3'0" × 7'0" or 3'6" × 8'0").
• Single or pair.
• Frame type (narrow, medium, or wide stile).
• Bottom rail height (standard 4", medium 6", wide 10").
• Hardware set: closer, pivot or butt hinges, lock, handle, threshold, weather strip.
• Automatic operator (if ADA requires power assist).

Automatic doors

Powered swing or sliding doors are usually a separate spec section but are often installed by the glazier. Verify scope responsibility before bidding.

8. Waste and Tolerances

Glazing waste factor is lower than most trades because glass is cut to exact size at the factory.

Standard glazing waste factors

• IGU glass: 3–5% for breakage, shipping damage, rework.
• Aluminum framing: 5–10% for field cuts and splicing.
• Gaskets and seals: 10%.
• Silicone sealants: 15% (cut tubes, clean-up waste).
• Screws, anchors, fasteners: 10%.

Why tolerances matter

IGUs should be measured tight. Too big and they do not fit. Too small and they show gaps. Always check field dimensions before final release to the factory, especially on retrofit or tight-tolerance conditions. When in doubt, hold field measurement.

9. AI Glazing Takeoff

Glazing takeoffs are famously detail-heavy. A blueprint glazing takeoff on a 5-story building can take 40+ hours manually. AI-powered tools compress this dramatically.

What to expect from AI takeoff

• Automatic detection of glazed openings on elevations.
• Measurement of vision glass SF by system type.
• Mullion and transom grid counting.
• Cross-reference with glass type legend via OCR.
• Output by system: CW SF, SF SF, punched window counts, door counts.

10. Putting It All Together for Bid Prep

A complete glazing bid preparation workbook has these rows: curtain wall SF vision + SF spandrel + LF framing; storefront SF + LF framing; window wall SF; punched windows each; entrance doors each with hardware set; interior glazing SF; glass breakouts by type (clear low-E, tinted, laminated, spandrel); sealants; anchors and perimeter closures; shop drawing allowance; engineering allowance; field measure allowance; mobilization; crane or lift; installation labor hours. Always include a performance mockup allowance on larger projects. Glazing is the trade where a small takeoff error becomes an expensive field problem, so slow, careful review pays off on every job.