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Modern Performance, Classic Charm

Steel Look Windows

Our steel-look windows allow for ultimate style, performance and durability, and are the ideal choice for both new build properties and renovation projects to retain an authentic look and heritage widow look.

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Home / Steel Look Windows, Doors and Internal Screens / Steel Look Windows, Doors & Bifolds

Our Steel Look Windows

Steel Look Windows, Doors & Bifolds in a charming stone cottage setting.

Alitherm Heritage Casement

The Alitherm Heritage gives you the authentic look of traditional steel windows, slim sight lines, putty-line detail and all, with a fully thermally broken aluminium frame behind it. Perfect for listed buildings, conservation areas, or anywhere heritage character matters. Available in any RAL colour.

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Modern steel-look windows and doors in a city building.

Alitherm Heritage Tilt and Turn

A clever take on a classic. The frame keeps the slim profiles and putty-line detail of a traditional steel window, but the handle does two jobs: tilt it for safe everyday ventilation, or turn it fully open for cleaning the outside from indoors. Especially useful on upper floors and in apartments. Available in any RAL colour.

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Steel Look Windows

Our steel look aluminium windows replicate the slender sightlines and period detailing of traditional steel-framed Crittall windows, while delivering the thermal performance, security and low maintenance that modern aluminium provides. Manufactured using the Smart Alitherm Heritage system, each window features a 47mm frame depth with slim mullion and transom profiles that create the characteristic narrow face-widths associated with original steel fenestration.

The Alitherm Heritage casement window is our core steel look window, offering fixed, side-hung and top-hung configurations with authentic mechanical jointing. For projects requiring enhanced ventilation or easier cleaning at height, the Heritage Tilt and Turn variant provides dual-mode opening — inward tilt for secure background ventilation or full inward turn for unrestricted access — all within the same slim-profile aesthetic.

Cortizo also offers a steel look window option through their casement system, which incorporates a bevelled sash detail to create the steel look aesthetic. This is particularly useful where a project specifies Cortizo throughout and consistency of system is preferred. Learn more about our aluminium casement window options, including the Cortizo steel look variant.

Key Features

  • 47mm frame depth with slim heritage sightlines replicating original steel proportions
  • Polyamide thermal break technology — U-values from 1.4 W/m²K (double glazed) and 1.1 W/m²K (triple glazed)
  • Fixed, side-hung, top-hung and tilt-and-turn opening configurations
  • Authentic mechanical jointing and heritage-style ironmongery
  • Accepts 28mm double-glazed or 44mm triple-glazed sealed units
  • Full RAL colour range including heritage colours — matt black, graphite grey, bronze, and white
  • Suitable for conservation areas, listed buildings and Article 4 directions

Applications

Specified by architects for period property renovations, conservation area projects, barn conversions and contemporary new builds seeking an industrial aesthetic. Particularly suited to properties where planning officers require slim sightlines consistent with original steel fenestration.

Steel Look Aluminium Windows for modern homes in Focusin.

Steel Look Bifold Doors

Our steel look bifold doors extend the Crittall-style aesthetic into large-format openings, allowing entire walls to fold back and connect interior spaces with gardens, terraces and courtyards. The steel look bifold uses the same slim-profile heritage detailing as our windows, with narrow astragal bars dividing each leaf into traditional multi-pane configurations that echo period steel glazing.

Available in configurations from 2 to 7 leaves, with options to fold left, right or split from the centre, these doors provide the architectural drama of a full-width opening while maintaining the refined proportions of traditional steel framing. Each leaf features the characteristic narrow face-widths and clean sight-lines that define the steel look aesthetic.

For oversized steel look bifold applications — where panel dimensions exceed what standard steel look sections can accommodate — we use the Cortizo bifold extrusion with applied astragal bars and no housing detail. This innovative approach allows us to create steel look bifold doors at scales that would be impossible with conventional steel look profiles, while maintaining visual consistency across the elevation. See our oversized steel look doors section below for details on this approach.

Key Features

  • Heritage-style slim sightlines with multi-pane glazing configurations
  • 2 to 7 leaf configurations — fold left, right or split from centre
  • Flush threshold options for level access and seamless indoor-outdoor transition
  • High-security multi-point locking as standard
  • Polyamide thermal break for excellent thermal performance
  • Available in full RAL colour range — matt black and graphite grey most specified
  • Oversized options available using Cortizo bifold extrusion with astragal bars

Applications

Ideal for rear extensions, orangeries, kitchen-diners opening to gardens, and barn conversions where the steel look aesthetic needs to extend across wide openings. Frequently specified alongside steel look windows to create a cohesive elevation treatment.

Aluminium doors with a sleek steel finish, perfect for contemporary house designs and outdoor spaces.
Stylish steel-look aluminium doors with large glass panels for modern home design.

Steel Look Doors

Our steel look door range encompasses three distinct profile options, each designed to suit different architectural requirements and opening sizes. From the classic 48mm section that most closely replicates traditional Crittall steel framing, through the refined 25mm edge cut detail, to our oversized solution using Cortizo bifold extrusions — we offer a steel look door for every application.

All three variants share the same fundamental aesthetic: clean, rectilinear proportions with slim glazing bars that create the multi-pane appearance synonymous with industrial and heritage architecture. The choice between them depends on the desired visual weight of the framing, the size of the opening, and whether the project calls for a traditional or contemporary interpretation of the steel look style.

Stylish steel-look aluminium sliding doors for modern homes.
Aluminium doors with a steel finish, providing a sleek, contemporary look and seamless indoor-outdoo.

48mm Section Steel Look Doors

The 48mm section is our standard steel look door profile — the classic aluminium interpretation of traditional Crittall-style steel framing. With 48mm face widths on the mullion and transom bars, this profile delivers the bold, defined glazing bar proportions that characterise original steel doors from the early 20th century. It is the most widely specified steel look door profile for heritage renovations, conservation area projects and period property restorations.

Manufactured using the Smart Alitherm Heritage 60 door system, the 48mm section features a 60mm frame depth with an extended polyamide thermal break, achieving U-values from 1.4 W/m²K with standard double glazing. The profile accepts glazing units up to 36mm, accommodating both double and triple-glazed sealed units for projects where enhanced thermal or acoustic performance is required.

The 48mm face width strikes the ideal balance between visual authenticity and structural performance. It is wide enough to create the distinctive shadow lines and visual rhythm of traditional steel framing, while remaining slim enough to maximise the glass area and natural light transmission. Available as single doors, French doors and side-panel combinations with matching fanlights and sidelights.

Key Features

  • 48mm face widths replicating traditional Crittall steel framing proportions
  • Smart Alitherm Heritage 60 system — 60mm frame depth
  • Polyamide thermal break — U-values from 1.4 W/m²K (double glazed)
  • Single door, French door and combination configurations
  • Multi-point locking with heritage-style lever handles
  • Glazing options: clear, leaded light, Georgian bar patterns
  • Full RAL colour range including period-appropriate heritage finishes

Applications

Conservation areas, listed building renovations, period property extensions, barn conversions and any project where planning requirements or design intent call for a faithful reproduction of traditional steel door proportions.

Bifold doors with a steel look, providing seamless indoor-outdoor access and contemporary style.

25mm Edge Cut Steel Look Doors

The 25mm edge cut profile offers a slimmer, more refined interpretation of the steel look aesthetic. Rather than the bolder 48mm face widths of the standard section, the edge cut detail creates a 25mm chamfered edge on the glazing bars, producing a more contemporary and visually lighter door that still reads as distinctly steel look in character.

This profile is increasingly specified by architects working on contemporary projects where the industrial aesthetic is desired but with a more restrained, modern sensibility. The narrower 25mm detailing creates finer shadow lines and a greater proportion of glass to frame, resulting in a door that maximises light while retaining the geometric discipline of steel-framed architecture.

The 25mm edge cut is particularly effective in projects that blend period and contemporary elements — for example, a modern rear extension on a Victorian property where the steel look style provides the visual link to the original architecture, but the finer detailing signals the contemporary intervention. It pairs especially well with frameless glazing, structural glass roofs and minimalist interior schemes.

Key Features

  • 25mm chamfered edge detail — slimmer than standard 48mm steel look profiles
  • Greater glass-to-frame ratio for enhanced natural light
  • Contemporary interpretation of the classic steel look aesthetic
  • Polyamide thermal break for compliance with Building Regulations Part L
  • Available as single doors, French doors and side-panel combinations
  • Ideal for pairing with frameless glazing and structural glass elements
  • Full RAL colour range — matt black, anthracite grey and bronze most popular

Applications

Contemporary extensions to period properties, architect-designed new builds, loft conversions, and projects where a lighter, more refined steel look aesthetic is preferred. Particularly suited to schemes where frameless glazing and minimalist detailing are key design drivers.

Stylish steel-look aluminium sliding doors for modern homes.

Oversized Steel Look Doors

For large-format steel look doors that exceed the dimensional limits of standard steel look aluminium sections, we use an innovative approach: the Cortizo bifold extrusion with applied astragal bars and no housing detail. This allows us to manufacture steel look doors at scales that would be structurally impossible with conventional 48mm heritage profiles — panels of 1200mm wide and up to 3000mm high, with the visual appearance of traditional multi-pane steel framing.

The Cortizo bifold extrusion provides the structural backbone — a robust 73mm frame depth rated for panels up to 120kg — while precision-applied astragal bars create the characteristic steel look glazing pattern on the external face. By eliminating the housing detail (the rebated step typically visible on standard steel look profiles), the astragal bars sit flush against the glass, creating a clean, contemporary interpretation of the steel look aesthetic at a dramatically larger scale.

This approach is particularly valuable for grand entrance halls, double-height glazed walls, large-format pivot doors and feature openings where the steel look aesthetic needs to be maintained at a scale that standard profiles cannot deliver. The Cortizo system also supports configurations of up to 7 leaves per side (14 total), making it suitable for the widest openings.

Key Features

  • Cortizo bifold extrusion — 73mm frame depth, panels up to 120kg
  • Applied astragal bars with no housing detail for clean flush finish
  • Panel dimensions up to 1200mm wide x 3000mm high
  • Steel look aesthetic at scales impossible with standard heritage sections
  • Polyamide thermal break — excellent thermal performance
  • Multi-leaf configurations for wide openings
  • Full RAL colour range with consistent finish across all components

Applications

Double-height entrance screens, grand reception rooms, large-format feature openings, contemporary barn conversions with oversized openings, and any project where the steel look aesthetic needs to work at a scale beyond the capacity of standard steel look aluminium profiles.

Elegant steel look bifold doors enhancing the house's contemporary design.

Steel Look Arched Doors

Steel Look Arched Doors

For arched aluminium windows in matching heritage profiles, see our dedicated range. For heritage properties and conservation areas, our steel look arched doors combine curved aluminium profiles with authentic steel-look astragal detailing. Each door is manufactured to bespoke dimensions, following the exact arch geometry of your existing openings.

View our full Steel Look Arched Doors range

Elegant arched glass door with black frame, leading to a balcony overlooking a cityscape.

Technical Specifications

Technical Specifications

Steel Look Windows — Alitherm Heritage

Specification Detail
System Smart Alitherm Heritage 47
Frame Depth 47mm
Thermal Break Extended polyamide
U-value (double glazed) From 1.4 W/m²K
U-value (triple glazed) From 1.1 W/m²K
Glazing Capacity 28mm (double) / 44mm (triple)
Opening Types Fixed, side-hung, top-hung, tilt & turn
Window Energy Rating A-rated (with correct specification)
Air Permeability Class 4 (600 Pa)
Water Tightness Class 9A (600 Pa)
Wind Resistance Class C4 (1600 Pa)
Acoustic Performance Up to 45 dB reduction

48mm Section Steel Look Doors — Alitherm Heritage 60

Specification Detail
System Smart Alitherm Heritage 60
Frame Depth 60mm
Face Width 48mm
Thermal Break Extended polyamide
U-value (double glazed) From 1.4 W/m²K
Glazing Capacity Up to 36mm
Configurations Single, French, with sidelights/fanlights
Security Multi-point locking

Oversized Steel Look Doors — Cortizo Bifold

Specification Detail
System Cortizo Bifold with astragal bars
Frame Depth 73mm
Max Panel Weight 120kg per leaf
Max Panel Width 1200mm
Max Panel Height 3000mm
Thermal Break Polyamide
Glazing Capacity Up to 48mm
Max Leaves 7 per side (14 total)

Glass Options

All our steel look windows, doors and bifolds are available with a choice of high-performance glazing to suit your project requirements:

  • Double-glazed sealed units — standard specification for thermal efficiency
  • Triple-glazed units — enhanced thermal and acoustic performance
  • Acoustic laminated glass — for noise reduction in urban and roadside locations
  • Solar control glass — reduces heat gain and glare while maintaining natural light

We specify the optimal glass configuration for each project based on thermal performance, acoustic requirements and Building Regulations compliance.

Colours & Finishes

Colours & Finishes

Our steel look windows, doors and bifolds are available in three premium finish categories — anodised, matt RAL and textured RAL — with dual-colour options allowing a different finish inside and outside. Woodgrain foil finishes are also available for a natural timber-effect appearance.

Popular RAL Colours

  • RAL 7016 Anthracite Grey
  • RAL 9005 Jet Black
  • RAL 7021 Black Grey
  • RAL 9010 Pure White
  • RAL 9001 Cream White
  • RAL 7012 Basalt Grey
  • RAL 7022 Umbra Grey
  • RAL 6009 Fir Green
  • RAL 8014 Sepia Brown

Any standard RAL colour is available to order. Heritage bronze and satin black anodised finishes are particularly popular for steel-look installations, complementing the industrial aesthetic.

Hardware & Handles

Hardware & Handles

Our steel-look range features premium art deco handle options designed to complement the industrial aesthetic. Every handle is selected to match the period-authentic detailing of the Alitherm Heritage system.

Handle Options

  • Lever handles: Art deco lever handles in heritage bronze, satin black and polished chrome finishes
  • Pull bars: Premium pull bar handles for doors — available in matching heritage finishes
  • Monkey tail handles: Traditional monkey tail espagnolette handles for an authentic period look
  • Tilt & turn handles: Low-profile inline handles for tilt and turn windows in matching finishes

All hardware is colour-matched to complement your chosen frame finish, maintaining the authentic steel-look aesthetic throughout.

Frequently Asked Questions About Steel Look Windows

Find answers to commonly asked questions about these stylish and durable windows crafted by Direct Trade Windows.

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What is the difference between 48mm, 25mm edge cut and oversized steel look doors?

The 48mm section is the classic steel look profile with 48mm face widths that most closely replicate traditional Crittall steel framing. It is the most widely specified for heritage renovations and conservation areas. The 25mm edge cut offers a slimmer, more refined 25mm chamfered detail that creates a contemporary interpretation of the steel look aesthetic with greater glass-to-frame ratio. The oversized option uses Cortizo bifold extrusions with applied astragal bars, enabling steel look doors at scales that standard profiles cannot achieve — panels up to 1200mm wide and 3000mm high. Each variant suits different architectural requirements, and our team can advise on the optimal choice for your project.

What thermal performance do steel look windows and doors achieve?

All our steel look products feature polyamide thermal break technology for excellent thermal performance. Steel look windows using the Alitherm Heritage system achieve U-values from 1.4 W/m²K with double glazing and 1.1 W/m²K with triple glazing, comfortably exceeding Building Regulations Part L requirements. Steel look doors using the Heritage 60 system achieve U-values from 1.4 W/m²K. Oversized steel look doors using the Cortizo bifold system also incorporate a polyamide thermal break. All products can be A-rated for window energy performance when fabricated with the correct specification.

Are steel look windows and doors suitable for conservation areas and listed buildings?

Yes — steel look aluminium windows and doors are widely accepted by conservation officers and planning authorities as a high-performance alternative to traditional steel framing. The slim sightlines and heritage proportions of the Alitherm Heritage system closely replicate original steel fenestration, making them suitable for conservation areas, Article 4 directions and listed building projects. We regularly work with architects and planning consultants on sensitive heritage projects across Surrey, London and the South East, and can provide technical drawings and specification documents to support planning applications.

What are the key features of steel look windows from Direct Trade Windows?

Our steel look windows are manufactured using the Smart Alitherm Heritage system, featuring a 47mm frame depth with slim heritage sightlines that replicate traditional steel proportions. Key features include polyamide thermal break technology for excellent thermal performance, fixed, side-hung, top-hung and tilt-and-turn opening configurations, authentic mechanical jointing, heritage-style ironmongery, and the full RAL colour range including matt black, graphite grey and heritage colours. Every window is manufactured in-house at our Surrey facility to your exact specification.

What colour options are available for steel look windows and doors?

All steel look products are available in the full RAL colour palette, polyester powder coated to BS EN 12206. The most popular finishes are matt black (RAL 9005), graphite grey (RAL 7024), anthracite grey (RAL 7016) and bronze. Dual-colour options are available — for example, matt black externally with white internally. All finishes carry a minimum 25-year guarantee against peeling, cracking and fading.

Can steel look doors be used for large openings?

Yes. Our oversized steel look door option uses the Cortizo bifold extrusion with applied astragal bars, enabling panels up to 1200mm wide and 3000mm high with a maximum leaf weight of 120kg. This approach allows steel look aesthetics on double-height entrance screens, grand reception rooms and feature openings that standard heritage profiles cannot accommodate. For standard openings, our 48mm section and 25mm edge cut profiles are available as single doors, French doors and bifold configurations.

How do steel look aluminium windows compare to traditional steel Crittall windows?

Steel look aluminium windows offer several significant advantages over traditional steel: substantially better thermal performance (U-values from 1.1 W/m²K versus 5+ W/m²K for single-glazed steel), lower maintenance with no risk of rust or corrosion, improved security with modern multi-point locking, and a considerably lower cost. The Alitherm Heritage system replicates the slim sightlines and proportions of original steel framing so faithfully that the difference is virtually indistinguishable from the external elevation.

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Cortizo logo FENSA logo BFRC logo Accreditation logo for Direct Trade Windows company. Constructionline Gold Member badge for trusted building industry standards. Close-up of a window with a focus on the frame and glass. Aluminium window with sleek design and modern finish.