Completed L-shape floating staircase — RAL 9005 steel spine, 100mm solid oak treads, 12mm toughened glass balustrade, LED-lit oak platform

The Brief — What the Client Needed

The homeowner was renovating a property in Romsey and wanted to replace a dated enclosed timber staircase with an open, contemporary floating design. The stairwell had an L-shape configuration — the staircase needed to rise straight, turn 90° at a quarter-turn platform, and continue to the upper floor. The key requirements: the steelwork had to disappear visually (jet black powder coat against a dark background), the oak had to feel solid and substantial, and the glass balustrade had to let maximum light into the hallway below.

The floor-to-floor height of 2,950mm with the available footprint produced a 38.8° pitch — comfortably under the Part K maximum of 42°, which gives a noticeably gentler climb than a staircase at the regulatory limit. The rise of 197mm and going of 245mm put the 2R+G comfort calculation at 2(197) + 245 = 639mm — right in the sweet spot of the 550–700mm range.

Entrance view — the staircase as you walk into the hallway

Front view — steel spine, oak treads, glass balustrade, black handrail

The Design — Every Component

1 Steel spine & structure

The structural backbone is a steel central spine running the full length of the lower flight, with tread support brackets (TS1) welded at 197mm rise intervals on both sides. Each tread sits on a pair of TS1 brackets — cantilevered from the spine on the open side, and supported by wall brackets (B1–B4) on the wall side. The spine connects at the bottom via mounting plate MP1 to the ground floor slab, and at the quarter-turn to the platform frame via MP2 and MP3 connections.

The platform frame is a separate welded steel assembly — a rectangular frame that supports the three oak platform pieces and transfers load into the walls at the corner. The upper flight uses the same bracket system to carry the remaining treads from the platform to the upper floor.

Everything steel was powder coated RAL 9005 jet black before delivery to site. The satin black finish absorbs light and recedes visually — the eye reads the staircase as floating oak treads and glass, with the steel structure disappearing into the background.

Central spine — RAL 9005 jet black, tread support brackets visible

Production drawing — spine assembly, wall brackets, platform frame dimensions

2 Oak treads & platform

12 solid oak treads at 900×275×100mm — each one identical, cut from the same batch of kiln-dried oak for consistent colour and grain. At 100mm thickness, the treads have a substantial visual presence and provide the structural depth to span from the spine bracket to the glass fixing point without perceptible flex underfoot.

The quarter-turn platform is the design centrepiece — a 3-piece oak assembly that wraps around the corner of the L:

Platform 2.1 (900×980×100mm) — the landing at the top of the lower flight. Platform 2.2 (1,818×1,410×100mm) — the main L-shape platform, the largest single oak element in the project. Platform 2.3 (1,328×1,165×100mm) — the transition to the upper flight, with a CNC-routed LED groove along the front edge for integrated under-platform lighting.

Below the oak platforms, fascia boards (20mm oak) clad the steel platform frame from below — Platform 3.1 (1,115×1,228mm) and Platform 3.2 (1,360×1,718mm). These conceal the steelwork completely when viewed from the ground floor, so the underside of the platform reads as a continuous oak surface rather than exposed steel.

100mm solid oak treads — end caps fitted, bolt fixings concealed

3-piece oak platform — LED groove illuminated, fascia boards below

Lower flight meeting the quarter-turn platform — seamless oak transition

Production drawing — tread 900×275×100mm, platform detail, end caps, assembly breakdown

3 Glass balustrade & handrail

12mm toughened clear glass panels running the full length of the open side — from the bottom tread, up through the quarter-turn, to the upper landing. The glass provides the guarding barrier required by Part K while maintaining full visual transparency through the stairwell. Light from the upper floor and the platform LEDs passes through the glass unobstructed, keeping the hallway below bright.

The handrail is a 40×40mm section in black — matching the RAL 9005 steelwork rather than the oak. This was a deliberate design choice: the black handrail reads as a continuous line from the steel spine up through the glass to the upper landing, tying the steel and glass elements together visually. End caps finish the handrail terminations cleanly.

Upper landing — 12mm toughened glass balustrade, 40×40mm black handrail

Full specification — 3D view, plan, sections, all dimensions annotated

4 LED platform lighting

LED strip lighting is recessed into a CNC-routed groove along the front edge of Platform 2.3. The groove is cut into the underside of the oak at a precise depth that conceals the LED strip from direct view — you see the light wash, not the source. The effect illuminates the upper treads and the glass balustrade from above, creating a warm ambient glow at night without needing overhead stairwell lighting.

This is an increasingly popular feature on our floating staircases — for more on how we integrate LED lighting into oak and steel staircase designs, see our floating staircases with LED lighting guide.

Installation — From Steel Frame to Finished Staircase

The installation followed a specific sequence designed to minimise time on site and protect finished surfaces:

1 Steel spine & platform frame

The steel spine and platform frame were installed first — bolted to the ground floor slab, fixed to the walls via brackets B1–B4, and levelled precisely before tightening. This is the structural skeleton that everything else attaches to. At this stage the staircase looks like raw black steelwork — functional but not finished.

2 Oak platforms & fascia

The three oak platform pieces were lifted into position on the steel frame and bolted down. Fascia boards were fitted below to clad the steel. LED strip was installed in the routed groove before the platform was secured — you can't access the groove afterwards.

3 Oak treads & end caps

Treads were fitted from bottom to top, bolted to the TS1 brackets through pre-drilled holes. End caps were glued and pinned to cover the exposed tread ends. Cover caps were pressed into the bolt holes for a clean finish.

4 Glass & handrail

Glass panels were fitted last — point-fixed through pre-drilled holes, with the handrail mounted on top. Fitting glass last protects the panels from damage during the oak and steel installation.

Step 1 — Steel spine and platform frame installed

Step 2 — Oak platforms fitted onto steel frame

Complete — treads, glass, handrail, LED all fitted

Technical Specification — Materials & Dimensions

Compliance — Regulations & Standards

3D proposal model — how the staircase was presented before fabrication began

Production drawings — 3-piece platform, fascia boards, LED groove, steel frame

Project Data — At a Glance

For more floating staircase projects and pricing, see our bespoke staircase product page. L-shape floating staircases with glass balustrade start from £9,500. For a full pricing breakdown, see our bespoke staircase cost guide.