Stone Dry-Hanging Calculator
Mullions, rails, brackets and panels in one pass.
With the default inputs: Wall width 30 · Wall height 20 · Panel width 0.9 etc.Stone panels incl. waste 822 blocks
Edit the inputs below to recalculate.Inputs
Result
| Panels (net) | 782blocks |
| Panels with waste | 822blocks |
| Mullions | 26bars |
| Mullion length | 520.0m |
| Rail rows | 24courses |
| Rail length | 720.0m |
| Total steel length | 1240.0m |
| Steel weight | 5580kg |
| Brackets | 3128pcs |
| Steel per m² | 9.3kg/m² |
| Brackets per m² | 5.21pcs/m² |
Typical construction: mullions at 1.0-1.2 m, rails aligned with panel height (usually 0.9-1.0 m), four brackets per panel at the corners. Steel content normally runs 8-12 kg/m² including mullions, rails and connections (channel mullions about 8 kg/m, 50x5 angle rails about 3.8 kg/m; this tool uses a blended weight per metre), higher for complex shapes and very large panels. Stone waste is 3-8%, at the top of the range with many cuts, book-matched joints and openings. Back bolts, cast-in plates, fire and insulation layers are excluded, and no structural check is performed - section sizes and anchorage capacity must be designed to JGJ 133.
Reverse: known result, work out one input
Enter a target result; the other inputs stay fixed and this one is worked out.
Formula
| Panels = ceil(W ÷ panel W) × ceil(H ÷ panel H) | |
| Mullions = ceil(W ÷ spacing) + 1; length = count × H | |
| Rails = ceil(H ÷ spacing) + 1; length = count × W | |
| Brackets = panels × 4 | four corners each |
How to work it out
- Set the grid first: panel module width and height give the panel count, and mullion spacing is normally 1.2 m aligned to the module or the brackets will miss the mullions.
- Mullions = wall width ÷ spacing, rounded up plus one; each runs the full height, so total length = count × height.
- Transom levels = wall height ÷ transom spacing (usually the panel module height); total transom length = levels × wall width.
- Brackets = panels × 4, one at each corner. This is the safety-critical item and must not be counted as two per panel.
- Panel area = wall area × (1 + waste): 5% for granite, 8-10% for marble where veining must be matched.
Where it goes wrong
- Counting two brackets per panel — short-slot dry hanging uses four per panel; halving them halves the safety margin and panels come off in wind.
- Cutting every mullion to the actual storey height — steel comes in 6 m or 9 m stock; cutting at 4.2 m leaves 1.8 m of scrap, so nesting must run across storeys.
- Specifying 20 mm stone — dry-hung stone facade panels must be at least 25 mm; 20 mm belongs to adhered work or small low-level areas and is unsafe on a facade.
- Costing steel only, ignoring fire stopping — every floor slab edge behind a facade needs fire stopping, and the mineral wool and galvanised sheet are routinely left out.
Material and cost
Granite panels 200-600 CNY/m² (common grades 200-300, imported or special 500+), marble 400-1200. Galvanised steel mullions 15-25 CNY/m, stainless brackets 3-8 each. Installation 120-220 CNY/m², more for high rise or curved work.
On site
- Seal stone on all six faces, not just the front; unsealed backs let alkaline moisture migrate through and leave permanent water stains.
- Use 304 stainless brackets, 316 on the coast or in polluted air; 201 starts pitting within two years.
- Undercut anchors are safer than short slots at 15-25% extra cost, and are preferred for large panels and important work.
Basis
- JGJ 133-2001 Technical code for metal and stone curtain walls
- GB 50210-2018 Code for acceptance of building decoration, Chapter 11 (curtain walls)
- GB/T 21086-2007 Building curtain walls
FAQ
Why is dry hanging so much dearer than wet fixing?
Is 9 kg/m² of steel normal?
Why higher waste for shaped work?
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Stone Dry-Hanging Calculator. 2026-10-25. https://jianzhujisuan.com/en/stone-dry-hang