Balustrade Panel Layout Calculator — Panel Sizes, Gaps & Fixings
Enter your total run length and this calculator divides it into equal glass panels, sets the gaps, checks every gap against the 100mm sphere rule from Approved Document K, and counts the fixings — spigots, channel length or posts — plus the total glass weight for delivery and handling. The layout logic mirrors how the Continox workshop actually panels a run: equal panels, compliant gaps, no odd cut panel at the end.
Panel Layout Calculator
Run length in, cutting list out — with a live compliance check on every gap.
To panel a glass balustrade run: divide the total length into equal panels no wider than your system and handling limit (typically 1,200–1,500mm), with gaps between panels of 10–99mm — Approved Document K requires that a 100mm sphere cannot pass through any opening, including panel-to-panel gaps, the gap under the glass, and the gap at walls. Fixings: base channel runs the full length; spigots need a minimum of two per panel (three for panels over ~1,200mm on some systems); framed systems need a post at every joint plus the ends. Equal panel widths cost no more than random ones and look dramatically better.
The 100mm Sphere Rule — Where It Applies
The sphere rule exists for one reason: a child's head must not fit through any opening in a barrier. On a glass balustrade that means four places, and the panel-to-panel gap is only the most obvious one:
| Opening | Limit | Watch Out For |
|---|---|---|
| Between glass panels | < 100mm | Spigot systems with wide spacing for the "floating" look |
| Below the glass (floor to bottom edge) | < 100mm | Spigots lift the glass off the deck — check the underside gap |
| Glass to wall at run ends | < 100mm | Out-of-plumb walls open the gap toward the top |
| Between open stair treads (if applicable) | < 100mm | Open-riser staircases — treads must overlap 16mm minimum |
The four openings checked against the 100mm sphere rule on every Continox balustrade installation.
Why equal panels matter more than you'd think. Toughened and laminated glass cannot be cut or trimmed after processing — every panel is made to its final size. If a run is set out with a random "leftover" panel at the end, the eye catches it immediately, and a mis-measure means a £200–£600 replacement panel with a 1–2 week wait. Setting out equal panels from a verified site dimension is the single cheapest quality decision in the whole project — and it's why Continox measures every run on site before anything goes to the processor.
Fixings by System
Base channel: a continuous aluminium channel along the full run, fixed to the structure at roughly 200–300mm centres. The channel handles the layout tolerances — panels drop in and are wedged plumb — which is why channel systems are the default for staircases and premium runs. Spigots: individual clamps, minimum two per panel, three on wide panels; the glass takes all the load between them, so spigot systems usually need thicker glass than channel for the same duty — check with the glass load calculator. Posts: one at each panel joint plus both ends (panels + 1), with the posts and rail carrying the loads, allowing thinner infill glass.
Panels over ~50kg change the planWide panels in thick laminated glass get heavy fast — a 1,500 × 1,100mm panel in 21.5mm laminated weighs about 85kg, which means a three-to-four person lift or mechanical aids, and a different installation day rate. The calculator shows the total run weight; for per-panel weights and handling thresholds, use the glass weight calculator. Sometimes the cheapest layout is more, narrower panels — less glass cost per panel, no lifting kit, faster install.
Worked Example — 6m Balcony
A 6,000mm external balcony run, frameless spigots, 1,500mm max panel width, 20mm target gap. Five panels: 5 × width + 4 internal gaps + 2 end gaps (half-gap each end against walls) — the calculator solves this to five equal panels of 1,176mm with 20mm gaps, all compliant. Ten spigots (two per panel), and in 17.5mm laminated at 1,100mm high the run weighs 269kg of glass — delivered in five two-to-three-person lifts rather than one crane job, which is exactly the kind of decision that separates a smooth installation from an expensive one.
Panel Layout — FAQ
Common questions about glass balustrade panel sizes, gaps and fixings.
Surveyed, Made to Size, Installed Once
Continox measures every run on site, sets out equal compliant panels, and manufactures to the millimetre — toughened laminated glass as standard, fixed-price quotation within 24 hours, installed by our in-house team.