How to count aluminium joinery

1. What to take from the plan

For each type of unit note the width, the height, the number of identical units and the number of leaves. Take the profile widths and the bar length from the manufacturer’s data sheet: they are editable starting values in the tools, never a built-in reference.

2. Profiles, glass and bars

The frame is the perimeter of the unit. Each leaf is the perimeter of its own opening, which is smaller than the unit by the frame width on each side. The glass is the leaf minus the leaf profile on each side. The length is increased by the waste percentage, then divided by the bar length and rounded up to whole bars.

Worked example: two windows of 150 × 120 cm

Two leaves each, 5 cm frame and leaf profiles, 6 m bars, 10 % waste:

• Frame: 2 × (150 + 120) × 2 = 10.80 m, i.e. 2 bars.
• Leaves: 70 × 110 cm each, 14.40 m in all, i.e. 3 bars.
• Glass: 4 panes of 60 × 100 cm, 2.64 m² with waste.

Doors, shutters, extruded profiles and cladding

Stainless, steel and fire doors are counted in sheets: leaf area for each skin, and the number of sheets that cut them. A roller shutter is counted in slats (height ÷ slat height, rounded up), guide rails, winding tube and box. An extruded profile is weighed from its section: kg per metre = area in mm² × density ÷ 1000. Cladding is counted in panels with their joints, and in the support rails behind them.

What this does not cover

The count does not design the joinery: thermal, wind, acoustic and fire ratings, the profile series, the glazing build-up and the hardware come from the manufacturer and the joiner’s drawings. A fire door is only fire-rated as a certified assembly.