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CLASSIC PROFILE

Depth. Detail. Distinction.

Stepped window profiles add subtle shadow lines and traditional character — a timeless look with fully modern performance.

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TRADITIONAL DONE RIGHT

The Character Your Home Was Missing.

Perfect for replacements in established streets — keep the familiar stepped look your neighbourhood expects, lose the draughts.

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MADE TO MEASURE

Every Opening. Precisely Yours.

Surveyed, manufactured and fitted to your exact sizes with A-rated glazing and a 10-year guarantee on frames, glass and installation.

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Unyielding Weather Performance

Unyielding Weather Performance

The inherent overlapping stepped design provides superior weather deflection and fortress-level thermal efficiency.

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Engineered for Excellence

Engineered for Flawless Installation

Fit-and-forget reliability for premium builders. Exacting tolerances, dry-glazed finishing, and zero callbacks.

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Bespoke Finishes

Your Vision, Your Colours

Endless bespoke possibilities with dual-colour, marine-grade powder coating for a truly unique finish.

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Welcome to the pinnacle of architectural glazing. For those who refuse to compromise on aesthetics, performance, and structural integrity, the AluK 58BW Stepped Aluminium Window system represents the ultimate in bespoke fenestration. Designed for luxury residences, avant-garde architectural projects, and premium developments, this is not just a window; it is a definitive design statement.

Unlike standard flush systems, the AluK 58BW Stepped design offers a timeless, sophisticated shadow line. The distinct rebated casement overlaps the frame, providing extraordinary weather resistance and a classic architectural depth that commands attention. Whether you are a homeowner seeking to transform your living space, an architect drafting a masterpiece, or a builder delivering excellence, the AluK 58BW Stepped window is engineered to exceed every expectation.

The visual impact of the stepped profile cannot be overstated. It introduces a subtle, textured geometry to the building's facade, breaking up flat exterior planes with crisp, deliberate lines. When specified in contemporary shades, the play of light and shadow across the stepped aluminium frame throughout the day adds a dynamic, living quality to your property.
The Stepped Advantage: Timeless Design Meets Modern Aluminium
While flush windows have dominated recent minimalist trends, the stepped casement design—where the opening sash sits slightly proud of the outer frame—is a celebrated architectural hallmark that is seeing a massive resurgence in high-end design. The AluK 58BW system reimagines this classic silhouette using ultra-slim, aerospace-grade aluminium.

The result is a window that offers the best of both worlds: the robust, multidimensional aesthetic of traditional joinery, paired with the impossibly sleek sightlines and immense strength of contemporary aluminium. This prominent shadow line created by the stepped sash adds texture and visual interest to a building's exterior.

Furthermore, the stepped design inherently offers superior weather deflection. The physical overlap acts as a natural drip-line, guiding rainwater away from the structural seals and ensuring the interior of the property remains impeccably dry, even in the most severe coastal or high-altitude weather conditions.
Uncompromising Luxury for the Modern Homeowner
Your home is your sanctuary, and the windows you choose literally frame your world. Upgrading to the AluK 58BW Stepped system is an investment in unparalleled quality, security, and thermal comfort that will transform the way you experience your living space.

Masterful Aesthetics & Breathtaking Natural Light

Aluminium possesses an incredible strength-to-weight ratio. This allows the AluK 58BW to support vast expanses of heavy, energy-efficient glass using incredibly slim frames. By minimizing the frame and maximizing the glass, these windows flood your interiors with natural light, blurring the lines between your indoor sanctuary and the outside world.

Whisper-Quiet & Thermally Superior Comfort

Say goodbye to drafts, cold spots, and intrusive street noise. The AluK 58BW features an advanced polyamide thermal break—a sophisticated, highly engineered barrier within the aluminium frame that completely severs the thermal bridge, stopping heat from escaping and cold from entering.

Fortress-Level Security for Ultimate Peace of Mind

Peace of mind is priceless, and the safety of your family is paramount. The AluK 58BW Stepped system is rigorously tested to meet and exceed the stringent PAS 24 security standards and Document Q building regulations. Featuring advanced multi-point locking mechanisms, highly robust friction hinges, and the inherent, unyielding strength of extruded architectural aluminium, these windows offer formidable resistance against forced entry.
Precision Engineering for Visionary Architects
As an architect, your vision relies on specifying materials that can perform seamlessly without compromising the overarching design intent. The AluK 58BW Stepped window is the ultimate tool in your specification arsenal, bridging the gap between rigorous performance metrics and flawless aesthetic delivery.
Unrivalled Design Flexibility and Configuration
Every project is unique, and the 58BW system is built to adapt to your specific architectural demands. Available in top-hung, side-hung, fixed-light, and multi-light configurations, it allows for vast modular spans, towering vertical elevations, and bespoke ribbon windows.
Specifications That Speak for Themselves
Performance is not optional in modern architecture. The AluK 58BW system accommodates glazing thicknesses from 24mm up to 44mm, easily housing standard double glazing or high-performance acoustic triple glazing to meet strict Building Regulations, including the latest Part L and Part F updates.
Built for Builders: Seamless Installation, Zero Callbacks
Time on site is money, and the reputation of your building firm hinges on the quality of the materials you specify and the flawless execution of the finish. The AluK 58BW is designed explicitly with the installer in mind, offering a highly engineered, predictable, and robust fabrication that installs effortlessly and securely every single time.

 Engineered for Precision on Site

AluK is globally renowned for its exacting manufacturing tolerances and rigorous quality control. The frames arrive on site perfectly square, highly rigid, and ready for swift installation. The stepped design utilizes advanced glazing beads and high-quality EPDM gaskets that ensure a perfect, dry-glazed finish without the mess and unpredictability of wet sealants.

Fit and Forget Reliability

Protect your margins by reducing your snagging lists to zero. Architectural aluminium is virtually maintenance-free. Unlike timber or uPVC, it will not rot, rust, warp, or fade under severe UV exposure. The premium powder-coated finishes are highly resistant to scratching, blistering, and peeling.
Technical Specifications Overview: AluK 58BW Stepped
For the exacting professional specifying for high-end residential or commercial projects, here are the hard numbers that make the AluK 58BW Stepped system an industry leader:
  • Design Profile: Stepped (Rebated) Casement
  • Material Grade: High-grade Architectural Aluminium (Alloy 6063 T6)
  • Thermal Break Technology: Advanced Polyamide Barrier
  • U-Value Performance: Capable of achieving < 1.2 W/m²K (with appropriate triple glazing)
  • Glazing Capacity: 24mm to 44mm (Double or Triple Glazed)
  • Security Certification: Fully PAS 24 compliant and Document Q approved
  • Weather Testing: Exceeds BS 6375 Part 1 for Air, Wind, and Water resistance
  • Finish Options: Full RAL colour range, single or dual-colour, marine-grade powder coating (Qualicoat) available.
  • Guarantee: Comprehensive manufacturer warranties on profiles and finishes.
A Palette of Possibilities: Bespoke Powder Coating
Your project deserves far more than standard, off-the-shelf colours. The AluK 58BW Stepped system is finished using an advanced electrostatic powder coating process, curing the paint to the metal at extremely high temperatures for an incredibly durable, beautifully even finish.
Sustainable Luxury for the Eco-Conscious Era
In modern construction, luxury and sustainability must go hand-in-hand. Aluminium is widely considered the ultimate green building material because it is infinitely recyclable without any loss of structural quality or integrity. The AluK 58BW system is manufactured with sustainability at its absolute core, utilizing high percentages of recycled aluminium billets.
Request a Bespoke Consultation Today
The AluK 58BW Stepped window system is a highly premium architectural product that requires expert consultation, precise measurement, and careful specification. If you are planning a high-end residential renovation, drafting a custom architectural build, or sourcing the very best materials for a luxury property development, our dedicated technical team is ready to assist you at every step.

Contact us today to request comprehensive technical manuals, downloadable CAD details, physical frame samples, or to arrange a dedicated, no-obligation consultation for your upcoming project. Experience the definitive standard in architectural glazing. Elevate your property with the AluK 58BW Stepped Aluminium Window.
THE CLASSIC PROFILE
Precision Engineering Meets Period Authenticity.
Why the shadow line matters
Walk any Victorian street and the windows have depth: sashes that catch the light and throw a thin shadow. Flat modern windows can look wrong there. The stepped profile keeps that depth, so a replacement reads as "always been there" — which is exactly what planners want to see.
 Same engine, different face
Under the profile, stepped shares everything with our flush range: 1.2 W/m²K thermal performance, Class 9a weather rating, PAS 24 security, any RAL colour. You choose the face for the street; the numbers stay the same.
Stepped, flush — or ask us
The honest rule: modern home, go flush; period street or strict planning, go stepped. Torn? WhatsApp a photo of your elevation and we will tell you which we would fit and why — free, no obligation.
Frequently Asked Questions
The three questions every buyer asks first
Is stepped more traditional than flush?
Yes — the proud sash is the historic casement profile.
Does stepped cost more?
Broadly the same; the system is shared.
Which colours suit period homes?
Cream, heritage green, off-white and black lead the requests.
START YOUR PROJECT
Ready to Restore Your Home's Character?
Get a personalized quote for your stepped window project or ask our specialists which profile best suits your property.
A modern kitchen featuring a white marble island and large wooden double doors.
Handles, Hinges & Locks
Premium hardware, colour-matched to every frame
Each door and window is finished with market-leading hardware multi-point locking, TS007 3-star anti-snap cylinders, stainless-steel  running gear, concealed hinges, and a full range of lever, pull and  key-operated handles. Hover any handle to see it enlarge. Mix and match  to suit your home or project.
Lever - Anthracite
Lever - Anthracite
Smooth ergonomic lever in Anthracite Grey (RAL 7016M) - our most-specified door handle.
Lever - Matt Black
Lever - Matt Black
Matt Black lever for contemporary, architectural looks. Pairs with any frame colour.
Lever - White
Lever - White
Bright White lever for classic, clean interiors and traditional homes.
Lever - Polished Chrome
Lever - Polished Chrome
Polished Chrome lever - a timeless shine that suits modern and classic doors alike.
Lever - Satin Silver
Lever - Satin Silver
Satin Silver lever for a soft brushed finish that hides fingerprints.
Lever - Brushed Gold
Lever - Brushed Gold
Brushed Gold lever for a warm, premium statement. Gorgeous with Anthracite frames.
Quadra - Anthracite
Quadra - Anthracite
Square-edge contemporary lever in Anthracite Grey - clean architectural lines.
Quadra - Matte Black
Quadra - Matte Black
Matte Black square-edge lever - the ultimate modern door handle.
Quadra - Matte White
Quadra - Matte White
Matte White square-edge lever - fresh, bright, contemporary.
Quadra - Polished Chrome
Quadra - Polished Chrome
Polished Chrome square-edge lever for a mirror finish that lifts any door.
Quadra - Satin Silver
Quadra - Satin Silver
Satin Silver square-edge - subtle brushed sheen, easy care.
Quadra - Brushed Gold
Quadra - Brushed Gold
Brushed Gold square-edge lever - on-trend warm metal tone.
Window - Anthracite
Window - Anthracite
Espagnolette window handle in Anthracite Grey. Key-lockable option.
Window - Black
Window - Black
Black inline window handle - sleek and timeless. Child-safety key option.
Window - White
Window - White
White window handle for traditional and modern casements alike.
Window - Polished Chrome
Window - Polished Chrome
Polished Chrome window handle - a classic finish for any room.
Window - Satin Silver
Window - Satin Silver
Satin Silver window handle - a calm, practical, brushed finish.
Window - Brushed Gold
Window - Brushed Gold
Brushed Gold window handle - a beautiful accent on heritage windows.
Lift & Turn - White
Lift & Turn - White
White lift-and-turn handle - simple, strong, classic.
Lift & Turn - Chrome
Lift & Turn - Chrome
Chrome lift-and-turn handle - glossy, durable, easy clean.
Lift & Turn - Satin Silver
Lift & Turn - Satin Silver
Satin Silver lift-and-turn handle - brushed finish for a modern look.
Lift & Turn - Brushed Gold
Lift & Turn - Brushed Gold
Brushed Gold lift-and-turn handle - a warm luxury statement.
Lift & Turn - Anthracite
Lift & Turn - Anthracite
Heavy-duty lift-and-turn handle for patio sliders and bifold traffic leaves.
Lift & Turn - Black
Lift & Turn — Black
Black lift-and-turn handle - gym-grade multi-point gearing.
Lift & Turn — Jet Black
Lift & Turn — Jet Black
Deep matt black lift-and-turn for sliders and bifold traffic leaves.
Lift & Turn — Brushed Gold
Lift & Turn — Brushed Gold
Warm metallic statement handle for premium sliding doors.
Lift & Turn - Satin black
Lift & Turn - Satin black
Soft-sheen black that hides fingerprints on busy doors.
Lift & Turn — Anthracite Grey
Lift & Turn — Anthracite Grey
Colour-matched to RAL 7016 frames for a seamless look.
Rondo keyed handle
Rondo keyed handle
Child-safe keyed window handle - ideal for upstairs bedrooms and rentals.
Pull handle suite
Pull handle suite
Matching pull handle and escutcheon for entrance doors - bold or minimalist.
Concealed 3D hinges
Concealed 3D hinges
Hidden when closed — adjustable in three planes for a perfect reveal for life.
Multi-point locking
Multi-point locking
Anti-snap TS007 3-star cylinders, hook bolts and deadlocks on every door as standard.
Colour Range
Over 200 colours — powder-coated, textured & gloss
Hover over any swatch to see its RAL code. We finish every frame to order — matt, gloss, metallic or textured. Can't see your shade? Any RAL is available.
Anthracite Grey
RAL 7016M
Deep Black
RAL 9005T
HIPCA White
RAL 9910HG
Pastel Green
RAL 6019
Agate Grey
RAL 7038
Jet Black
RAL 9005M
Slate Grey
RAL 7015
Basalt Grey
RAL 7012
Light Grey
RAL 7035
Silver Grey
RAL 7001
Fir Green
RAL 6009
Moss Green
RAL 6005
Chocolate Brown
RAL 8017
Oxide Red
RAL 3009
Sapphire Blue
RAL 5003
Steel Blue
RAL 5011
Cream
RAL 9001
Sand Beige
RAL 1011
Anthracite Textured
RAL 7016 Matt T
Jet Black Textured
RAL 9005 T
Brushed Silver (Tex)
DB 701 T
Pewter (Textured)
RAL 7037 T
Brushed Bronze
DB 703 T
Olive Bronze
DB 604 T
Gold Metallic
AY 1050
Brushed Aluminium
AY 2050
Graphite Pearl
AY 900 M
Any RAL or BS colour available to order — just ask. Dual-colour (different inside / outside) supported on all ranges.
Explore the Range
More ways we transform homes & builds
Versatali Bifold Doors
Versatali Bifold Doors
Slim aluminium folding doors, huge glass spans, Part L ready. Supply or fit.
U-Value
1.1 W/m²K
Rating
A-B WER
Security
PAS 24
Explore bifolds
Front & Panel Doors
Front & Panel Doors
Bank-vault secure, optional ekey fingerprint entry, 120+ panel designs.
U-Value
1.1 W/m²K
Rating
A-B WER
Security
PAS 24
Explore front doors
Aluminium Windows
Aluminium Windows
Flat-flush modern casements, any configuration, 25% more glass than uPVC.
U-Value
1.1 W/m²K
Rating
A-B WER
Security
PAS 24
Explore windows
Heritage Windows
Heritage Windows
Authentic astragal bars, period look, modern Part L performance.
U-Value
1.1 W/m²K
Rating
A-B WER
Security
PAS 24
Explore heritage
Glass Internal Doors
Glass Internal Doors
Bifold, sliding or pivot. Open-plan when you want it, quiet when you do not.
U-Value
1.1 W/m²K
Rating
A-B WER
Security
PAS 24
Explore internal doors
Conservatory Roof Replacement
Conservatory Roof Replacement
Tiled, glass lantern or hybrid - reclaim your conservatory as a year-round room.
Roof U-value
from 0.15 W/m²K
Options
Tiled, glass or hybrid
Fitted
PAS 24
Explore roof replacement
Kitchen Extensions
Kitchen Extensions
Full-build rear and side extensions with trusted partner builders - concept to keys.
Build time
12–16 weeks
Service
Concept to keys
Glazing
Part L ready
Explore extensions
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Glazed Window Systems
About Us
We specialise in premium glazed doors and windows, combining modern design with lasting durability to enhance residential and commercial spaces across the UK. Crafted with precision and built to perform, our products bring light, style, and value to every project.
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Glazed Window Systems Limited
Flexspace Unit 12, Middlemore Road, West Bromwich, Birmingham, B21 0BN
© 2025 Glazed Window Systems Limited. All rights reserved.
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