Glazing takeoff and estimating

What to read

• Exterior elevations with storefront, curtain wall and window layouts.
• Window and storefront schedules with types, sizes and glass tags.
• Details for sills, heads, jambs, anchors, flashing and the air-barrier interface.
• Specifications: systems, glass makeups, finishes, performance criteria, delegated design, mockups, testing, warranty.
• Door hardware schedule for glazed doors.
• Code plan or life-safety sheets for rated glazing.

Take off by opening

Field	Why
Elevation and location	Source and traceability
System type	Storefront, curtain wall, window wall, punched window
Width × height	Area and perimeter
Mullion layout	Frame LF and lite count
Glass type(s) per lite	Glass area by makeup; safety and rated lites
Doors	Count, size, hardware set
Floor / elevation height	Access equipment and hoisting

Worked example: one storefront opening (illustrative)

Opening SF-1: 20 ft wide × 10 ft high, 4 equal bays (verticals at 5 ft), one horizontal at 7 ft 6 in (transom line), no doors:

Item	Calculation	Quantity
Perimeter frame	2 × (20 + 10)	60 LF
Intermediate verticals	3 × 10	30 LF
Horizontal	20	20 LF
Total frame		110 LF
Lites	4 bays × 2 (vision + transom)	8 lites
Glass area (gross, before sightline deductions)	20 × 10	200 SF
Perimeter sealant	60 LF exterior + 60 LF interior	120 LF

If the opening sits beside an entrance door, check IBC 2406.4: lites whose nearest edge is within 24 in of the closed door edge with the bottom under 60 in must be safety glazing. Here, the lower vision lite in the bay next to the door would need safety glazing even if the elevation doesn't tag it. The transom above it starts at 7 ft 6 in, so the 60 in condition doesn't apply.

Order glass by actual lite size from shop drawings. Takeoff glass area is for pricing, not ordering.

Storefront, curtain wall and window wall

System	Typical use	Takeoff notes
Storefront	Ground floor, single-story openings	Frames by elevation; doors and hardware separate
Curtain wall (stick)	Multi-story façades	Mullions, transoms, anchors, glass by lite; scaffold or lifts
Curtain wall (unitized)	High-rise, schedule-driven	Units by type; shop-built; crane or hoist installation
Window wall	Spans slab to slab	Slab-edge covers and perimeter fire-safing details

Unitized systems move labor into the shop and need hoisting on site. Stick systems need more field labor and access.

Glass: taking off lites

Glass is ordered by lite, with size and makeup: insulating units with coatings, tempered or laminated where required, spandrel, and fire-rated glass where specified. Separate spandrel and shadow-box areas from vision glass. Watch for:

• Safety glazing in the hazardous locations of IBC 2406.4: in and near doors, large low lites near walking surfaces, guards and railings, wet areas, and stairs and ramps.
• Fire-rated glazing in rated walls and doors, which is a different product and price.
• Bird-safe or patterned glass where local ordinances require it.
• Attic stock and breakage allowances if the spec requires them.

Perimeter and interfaces

Sill flashing, sealant, backer rod and the tie-in to air barriers and roofing are frequent scope disputes. Measure perimeter sealant in LF by joint type, and read the responsibility matrix for who connects the frame to the wall's air and water barrier.

Engineering, mockups and testing

Many curtain wall specs require:

• Delegated design by a licensed engineer, with stamped calculations.
• Performance mockups tested in a lab, with location, size and retest terms.
• Field water testing: AAMA 501.2 is a hose-nozzle check (a calibrated nozzle at 30 to 35 psi on 5 ft sections, 5 minutes each). ASTM E1105 uses a spray rack with a static or cyclic air pressure difference. Under AAMA 503, the field test pressure is typically two-thirds of the rated lab pressure. AAMA's standards are now maintained by FGIA.

Price each as its own line: number of tests, locations, access, the testing agency, and an allowance for retests.

Doors and hardware

Aluminum entrances are counted by type and size, with hardware sets from the hardware schedule: hinges or pivots, closers, exit devices, locks, and electrified hardware with power transfer for access control. Hardware often comes from a separate supplier, so confirm what the glazing scope includes.

Glazing qualifications

• Delegated engineering and stamped calculations: included or excluded.
• Mockups and field testing: quantity, method, retests.
• Hoisting, cranes and swing stages: by whom.
• Perimeter sealant at adjacent materials and air-barrier tie-in: by whom.
• Glass breakage after installation: by others.
• Final cleaning: included or excluded.

Common misses

• Untagged safety-glazing lites near doors and floors.
• Spandrel areas priced as vision glass.
• Door hardware assumed by someone else.
• Access equipment above the first floor.
• Testing and retests buried in overhead.

Where RenderDraw fits

RenderDraw's AI takeoff proposes opening counts, sizes and facade areas from elevations, plans and schedules, keeps the source on every row, and sends uncertain items to review. Your system rules, glass makeups and pricing apply after approval.