Shady Bower Block 3, Salisbury SP1 — 3D design model showing all balcony railing positions across the building elevation

The Brief — What the Client Needed

The developer was refurbishing a multi-storey residential block at Shady Bower Close in Salisbury and needed a complete set of balcony railings across the building. The existing railings had reached end-of-life — corroded, non-compliant, and visually dated. The replacement needed to meet current Building Regulations (Part K), integrate with the existing balcony structure without major structural modification, and deliver a clean, modern appearance consistent with the refurbishment programme.

The key constraints were: every balcony had a slightly different configuration (different widths, return panels, corner conditions), the railings needed to fix onto existing concrete and steel balcony slabs using bolt-on mounting plates rather than cast-in fixings, and the entire package needed to be designed as modular assemblies that could be transported and installed efficiently on site.

What We Designed — 6 Assemblies, 36 Drawings

We produced a full set of V2 production drawings — 36 sheets covering 3D views, assembly views, parts breakdowns, individual component details, post details, and mounting plate DXF files for laser cutting. Every assembly was modelled in 3D before fabrication began.

B1 Balcony 1 — right elevation, floors 1–2

Full-width railing spanning 4,158mm across the front face with a 1,300mm deep return on the side elevation. Three railing panels (B1R1, B1R2, B1R3) bolted to five posts (B1P1–B1P5) via laser-cut mounting plates. The main front panel (B1R2) spans 2,792mm with 15×15 SHS spindles at 85mm centres. Overall height: 1,055mm above the balcony slab (1,360mm total post height including the sub-slab fixing depth of 235mm).

B2 Balcony 2 — right elevation, floor 3

Identical configuration to B1 — same dimensions, same panel layout, same post details. Designed as a mirror assembly to maintain visual consistency across the elevation. Parts are interchangeable with B1, reducing fabrication time and material waste.

B3 Balcony 3 — left elevation, floors 1–2

Wider overall footprint at 4,330mm across the front face (vs 4,158mm on B1/B2), with a deeper return at 1,322mm. The railing panel layout mirrors B1 but with adjusted spindle spacing to accommodate the wider span. Posts are 40×40 SHS throughout, with the same MP1–MP5 mounting plate system.

B4 Balcony 4 — left elevation, floor 3

Mirror of B3 — identical dimensions and part configuration. Again designed for part interchangeability with B3 to streamline production.

JB1 Roof terrace railing

The largest assembly in the package — a full-length roof terrace railing spanning 4,075mm with taller posts at 1,515mm (vs 1,360mm on the floor balconies). Five posts (P1 ×2, P2 ×3) support a continuous railing panel with 15×15 SHS spindles at 85mm centres. The additional post height accommodates the raised parapet and achieves the required 1,100mm barrier height above the terrace walking surface. Posts are fixed via 450mm base plates with four M14 anchor bolt positions each.

JB2 Juliet balcony

A compact single-panel Juliet balcony unit — 1,105mm wide × 1,055mm high, mounted on two posts with 585mm centres. 40×40 SHS frame with 15×15 SHS spindles at 85mm centres. Fixed to the facade via MP3 base plates (150mm × 200mm × 10mm S275) with four M14 anchor positions. Designed as a standalone unit — no platform, no external access, no planning permission required (permitted development under the standard Juliet balcony exemption). For more on Juliet balcony planning rules, see our planning permission guide.

Ground level balcony detail — railing panels, posts, and mounting plates visible

Roof terrace railing close-up — taller posts with base plate mounting

B1 assembly — front elevation (V-A), side elevation (V-B), plan view (V-C)

B1R2 main railing panel — 2,792mm span, 20× rivet nut fixing positions

Technical Specification — Materials & Components

Fabrication Detail — How We Built It

The project was fabricated entirely in-house at our workshop in Portsmouth. The production sequence followed a specific order designed to minimise handling and maximise accuracy across 6 near-identical assemblies.

Laser cutting

All 5 mounting plate types (MP1–MP5) were drawn as DXF files and sent to our laser cutting partner. Total: 153 individual plates cut from 6mm and 10mm S275 steel plate. Hole positions for M8 rivet nuts (Ø11mm) and M12 structural bolts (Ø12mm/Ø14mm) were cut at the same time as the plate profiles — no secondary drilling required.

Post fabrication

Posts were cut to length from 40×40mm SHS, with MP2 connection plates welded at the specified positions (top and bottom of each post). Base plates (MP3 or MP4) were welded to the foot of each post with full-penetration fillet welds. Each post type (P1–P5 per balcony) has slightly different plate positions and configurations — we used the production drawings as jigs, marking positions directly from the dimensioned drawings.

Panel fabrication

Railing panels were assembled as complete frames — 40×40 SHS top and bottom rails with 15×15 SHS spindles welded at 85mm centres. MP1 end brackets were welded to the panel frame at each end. Rivet nut positions were drilled at Ø11mm after welding to ensure alignment with the post connection plates. Each panel was fabricated as a single transportable unit.

Powder coating

All components — panels, posts, and loose mounting plates — were shot-blasted, pre-treated, and powder coated to the client's specified RAL colour. Panels and posts were coated as completed assemblies; loose plates were coated separately and bagged per assembly to prevent site mix-ups.

Post fabrication details — 5 post types per balcony, each with specific plate positions

Panel detail — 40×40 SHS frame, 15×15 spindles at 85mm centres, M8 rivet nut fixings

Compliance — Regulations & Standards

The balcony railings were designed to comply with the following UK Building Regulations and British Standards:

For the complete guide to balcony railing regulations, heights, and specifications, see our product page. For the full breakdown of Part K requirements across all guarding applications, see our UK staircase and balustrade regulations guide.

Project Data — At a Glance