Central Spine Staircases Designed & Installed
A single structural steel spine. Cantilevered treads open on both sides. Frameless glass balustrade the full height of both faces. The most architecturally striking contemporary staircase design available β and the most requested design at Continox. From Β£9,500.
A central spine staircase uses a single structural steel beam running from bottom to top β with each tread cantilevering from the spine on both sides. The result is a staircase that is entirely open on both faces, with no wall attachment required, no visible stringer and no visual support beneath the treads. Combined with frameless glass balustrades on both sides, it becomes the defining architectural feature of any open-plan space.
Central Spine Staircase Configurations
The central spine structural system is available in four main configurations β straight, L-shape, U-shape and Y-shape. Each uses the same single-spine engineering principle; the layout adapts to the specific stairwell geometry and space requirements.
L-Shape Central Spine
The most common central spine configuration for UK residential properties β a 90-degree turn at an intermediate landing, fitting neatly into the corner of an open-plan space. The spine changes direction at the landing with a structural knee joint, maintaining the single-beam aesthetic through the turn. Glass balustrade runs continuously on both sides of both flights and across the landing edge.
- Single structural steel spine β S275 or S355
- 90Β° turn β structural knee joint at landing
- Frameless glass balustrade both sides
- Oak or walnut treads β 40mm solid timber
- Brushed steel or timber-capped handrail
- LED under-tread integration available
U-Shape Central Spine
The staircase doubles back on itself β two parallel flights connected by a half-landing at 180 degrees. More compact in length than an L-shape but wider in plan, requiring a larger stairwell opening. The U-shape is the most dramatic central spine configuration, creating a symmetrical double-sided floating effect that is impressive from every angle and particularly striking viewed from the upper landing.
- 180Β° turn β half-landing platform
- Requires wider stairwell opening
- Frameless glass balustrade both sides + landing
- Oak, walnut or steel plate treads
- Ideal for double-height open plan spaces
- +Β£1,500βΒ£3,000 over L-shape specification
Straight Central Spine
A single uninterrupted flight from ground to upper floor β the purest expression of the central spine concept. The spine runs in a straight line beneath all treads, with glass both sides and the treads cantilevering symmetrically. Requires a clear linear run along the stairwell opening. Maximises light flow from a rooflight above, making it particularly effective in double-height spaces with natural light from above.
- Single straight spine β no turns
- Maximum visual impact β full flight visible
- Frameless glass both sides
- Ideal for double-height new builds
- Rooflight integration recommended
- Most cost-effective central spine configuration
Y-Shape & Custom Geometry
The central spine system is not limited to conventional rectangular layouts. Continox designs and fabricates central spine staircases in Y-shape configurations, angled layouts and fully bespoke geometries for architectural projects where the staircase is designed as a sculptural element rather than simply a means of access. Every non-standard geometry requires individual structural engineering β confirmed at the free on-site survey.
- Y-shape, angled and custom geometry
- Fully bespoke structural engineering
- 3D photorealistic visuals of exact design
- Any tread material and glass specification
- LED and handrail fully customised
- Architectural and commercial projects welcome
Worked Example: Real Project Cost Breakdown
The following is a real central spine L-shape staircase project β 13 treads, solid oak finish, frameless glass balustrade both sides, integrated LED lighting. This is the most popular specification at Continox.
Oak Treads Β· Frameless Glass Both Sides Β· LED
Excludes VAT. Includes free survey, 3D visuals, structural calculations, CAD drawings, UKCA marking and installation. Fixed price β no post-installation additions.
What's Included in Every Project
Every Continox central spine staircase includes the complete project from first site visit to Building Control sign-off β all at a fixed price confirmed following the free on-site survey.
Free On-Site Survey
Precise site measurements, structural substrate assessment, stairwell opening confirmation and floor finish thickness. All dimensions taken from site β never from drawings alone.
3D Photorealistic Visuals
Full photorealistic renders of your central spine staircase in your actual space β including material finishes, glass type, LED lighting and handrail profile. Produced before any fabrication.
Structural Calculations
Full structural engineering to BS EN 1090 β spine sizing, cantilever tread calculations, fixing design and material specification. Signed by a qualified structural engineer.
CAD Drawings β PDF & DWG
Detailed drawings showing all dimensions, spine layout, fixing positions and Part K compliance notes. Suitable for Full Plans Building Control submission by your architect.
UKCA Marking & DoP
All structural steel components carry UKCA marking and Declaration of Performance β a legal requirement and increasingly required by Building Control surveyors and commercial insurers.
Professional Installation
Installed by Continox's in-house team β no subcontractors. Typically 2β3 days on site for an L-shape central spine. Full compliance documentation handed over on completion.
Central spine vs floating staircase β which is right for your space? A central spine staircase is open on both sides and requires no wall attachment β it stands independently, typically anchored at the top and bottom floor plates. A floating staircase is wall-fixed, with each tread cantilevered into the adjacent wall. If your staircase is positioned in the middle of an open-plan space with sightlines from multiple directions, central spine is the right choice. If it runs along a wall with one open side, a floating staircase delivers excellent results at lower cost. See our floating staircase page for comparison.
How It Works: From Enquiry to Installation
Every Continox central spine staircase follows the same four-stage process β no surprises, no estimates, no post-installation additions to the agreed price.
Free On-Site Survey
We visit your site, take precise measurements and confirm the structural connection points at top and bottom. No charge. All dimensions confirmed on site β not from plans.
3D Design & Fixed Price
Photorealistic 3D renders of your central spine staircase in your actual space. Fixed-price quotation within 24 hours β covering design, structural engineering, fabrication and installation.
Manufacture
Spine fabricated in structural steel, treads machined to exact dimensions, glass cut and polished to specification. Structural calculations and CAD drawings produced concurrently.
Installation & Sign-Off
Installed by our in-house team β 2β3 days on site for a standard L-shape. UKCA documentation and compliance schedule handed over on completion. Lead time from order: 6β10 weeks.
The Most Requested Design at Continox
The central spine staircase consistently accounts for the majority of Continox's residential staircase projects β and for good reason. The combination of structural elegance, visual impact and design flexibility makes it the natural choice for homeowners who want a contemporary staircase that reads as an architectural feature rather than a utilitarian element.
Continox designs and installs central spine staircases across the UK β from Hampshire, Surrey and London to the Midlands and East of England. Every project is priced following a free on-site survey. For full pricing including upgrade options see our Bespoke Staircase Cost guide.
For design inspiration across all central spine configurations see our Modern Staircase Ideas UK guide and our completed project gallery.
Glass Balustrade on a Central Spine
The frameless glass balustrade is the defining complement to the central spine staircase β both are characterised by the elimination of visible structure. A central spine with frameless glass on both sides creates a staircase where the only visible elements are the spine beneath, the treads above it, and the glass panels on both sides. The structure appears almost entirely absent.
All Continox central spine installations use 17.5mm toughened & laminated glass (BS EN 14449) on frameless systems β the lamination ensures the glass remains a barrier in the event of breakage. For elevated positions or higher load requirements, 21.5mm or 25mm is specified. For the cleanest possible appearance, a low-iron ultra-clear glass upgrade eliminates the faint green tint of standard glass entirely.
For full glass specification details see our glass balustrade range and our Glass Balustrade Regulations guide.
Designed, manufactured and installed across the UK. Based in Hampshire β regularly delivering to London, the South East, South West and East of England.
Central Spine Staircase β FAQ
Common questions from UK homeowners about central spine staircase design, cost and installation.
Free on-site survey, photorealistic 3D visuals of your exact design, and a fixed-price quotation within 24 hours. Central spine staircases from Β£9,500 β designed, manufactured and installed across the UK.