The Ultimate Design
Elevate Your Architecture with
AluK 58BW Stepped Aluminium Windows
Uncompromising luxury, unparalleled strength. Discover the definitive architectural shadow line for high-end homes.
Explore the Stepped Collection
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Architectural Precision
Precision in Every Profile
Designed for visionary architects. The classic rebated casement reimagined in ultra-slim, aerospace-grade aluminium.
View Technical Specifications
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Natural Light & Interior Luxury
Frame Your World in Luxury
Maximise natural daylight and blur the lines between indoors and out with exceptionally slim stepped frames.
Transform Your Home
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Unyielding Weather Performance
Unyielding Weather Performance
The inherent overlapping stepped design provides superior weather deflection and fortress-level thermal efficiency.
Discover Thermal Benefits
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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.
Trade & Installer Portal
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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.
View Colour Palette
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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.
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Glazed Window Systems
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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
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