Crittall Style Doors: A Comprehensive UK Homeowner's Guide

Crittall style doors and windows have experienced a remarkable resurgence in popularity across the UK, captivating homeowners, architects, and interior designers alike. Their distinctive aesthetic, characterised by slim, dark frames and multiple glazing bars, offers a timeless blend of industrial chic and elegant sophistication. But what exactly are Crittall style doors, and what should UK homeowners consider before investing in them?

This comprehensive guide will delve into the world of Crittall style glazing, explaining its history, technical specifications, benefits, potential considerations, and crucial compliance with UK Building Regulations. Our aim is to provide you with the expert knowledge needed to make an informed decision for your home improvement project.

What Are Crittall Style Doors?

The term 'Crittall' originally refers to Crittall Windows Ltd, a British company founded in 1849, renowned for pioneering steel-framed windows and doors. Over the decades, their distinctive grid-like designs became synonymous with modern architecture, particularly during the Art Deco and Modernist periods. Today, 'Crittall style' has become a generic term for any glazing product that mimics this iconic aesthetic, typically featuring:

• Slim Steel or Aluminium Frames: The hallmark of the style, offering maximum glass area and a minimalist profile.
• Multiple Glazing Bars: Creating a grid pattern, often in a matt black or dark grey finish.
• Large Panes of Glass: Maximising natural light and creating a sense of openness.
• Industrial Aesthetic: A blend of robustness and elegance that suits both contemporary and traditional properties.

While original Crittall products are made from steel, many modern 'Crittall style' alternatives utilise aluminium. Aluminium offers a lighter, often more thermally efficient, and lower-maintenance option, while still achieving the desired visual effect. Understanding this distinction is key when evaluating options for your home.

Benefits of Crittall Style Glazing for UK Homes

The appeal of Crittall style doors extends beyond their striking appearance. They offer a range of practical and aesthetic advantages that make them a compelling choice for many UK homeowners.

Internal vs. External Applications

• Internal Doors: Often used as room dividers or screens, internal Crittall style doors create a sense of open-plan living while still providing acoustic separation and visual zoning. They allow light to flow freely between rooms, making smaller spaces feel larger and more connected.
• External Doors: When used externally, these doors become a focal point, offering impressive views of gardens or patios. They are commonly specified for extensions, conservatories, or as main entrance doors, requiring higher thermal performance and weather resistance.

Technical Specifications and UK Building Regulations (Part L)

For UK homeowners, understanding the technical specifications and how Crittall style doors comply with Building Regulations is paramount, especially for external applications. The key regulation here is Part L (Conservation of Fuel and Power), which sets standards for thermal performance.

U-Values and Thermal Performance

A U-value measures how effectively a material insulates. The lower the U-value, the better the insulation. For external Crittall style doors and windows, meeting the current (2022) Part L Building Regulations for England is crucial:

• New Build Properties: Windows/Doors must achieve a U-value of 1.2 W/m²K or lower.
• Replacement Windows/Doors (existing dwellings): Windows/Doors must achieve a U-value of 1.4 W/m²K or lower.

Achieving these U-values with slim-framed glazing requires advanced technology:

• Double Glazing: Essential for external applications. Look for units with a minimum of 24mm thickness, incorporating a low-emissivity (low-e) coating and argon gas filling in the cavity.
• Thermal Breaks: Modern steel and aluminium Crittall style frames incorporate thermal breaks. These are non-metallic barriers within the frame that prevent heat from conducting directly through the metal, significantly improving thermal performance. Without thermal breaks, metal frames would be highly inefficient and prone to condensation.
• Gaskets and Seals: High-quality EPDM gaskets and weather seals are vital to prevent draughts and water ingress, contributing to both thermal efficiency and weather resistance.

Other Relevant Building Regulations

• Part B (Fire Safety): For certain applications (e.g., doors to escape routes, or within specific distances of boundaries), fire-rated glazing might be required. This typically involves specialist fire-resistant glass and frame systems.
• Part K (Protection from Falling, Collision and Impact): Glazing in critical locations (e.g., low-level glazing, or adjacent to doors) must be safety glass (toughened or laminated) to prevent injury in case of breakage.
• Part F (Ventilation): If replacing windows or doors, ensure that the new installation maintains or improves the ventilation provision, or that adequate trickle vents are incorporated.

It is always recommended to consult with your local Building Control body or an experienced architect/designer early in your project to ensure full compliance with all relevant regulations.

Steel vs. Aluminium Crittall Style: A Comparison

While original Crittall products are steel, the market now offers high-quality aluminium alternatives. Understanding the differences is crucial for making the right choice for your home.

Feature	Steel Crittall Style	Aluminium Crittall Style
Material	Solid steel sections	Extruded aluminium sections
Frame Profile	Extremely slim, often narrower than aluminium. Highly authentic to original Crittall.	Very slim, but typically slightly wider than steel to accommodate thermal breaks and larger glazing units.
Thermal Performance (U-value)	Excellent, with advanced thermal breaks. Can meet 1.2-1.4 W/m²K.	Excellent, with advanced thermal breaks. Often slightly easier to achieve lower U-values due to material properties. Can meet 1.2-1.4 W/m²K.
Weight	Heavier, requiring robust structural support.	Lighter, often easier to handle and install.
Durability & Strength	Extremely strong and durable, highly resistant to impact.	Very strong and durable, resistant to corrosion.
Maintenance	Low maintenance, typically powder-coated. May require occasional inspection for rust if coating is damaged.	Very low maintenance, highly corrosion-resistant, typically powder-coated.
Cost	Generally higher due to material and manufacturing complexity.	Often more cost-effective than steel, offering a great balance of performance and price.
Aesthetic Authenticity	Closest to the original Crittall look and feel.	Excellent replication, often indistinguishable to the untrained eye.

For many homeowners, high-quality aluminium Crittall style doors offer a fantastic balance of aesthetic appeal, thermal performance, durability, and cost-effectiveness. However, if absolute authenticity and the slimmest possible sightlines are your priority, steel remains the premium choice.

Design and Installation Considerations

Choosing and installing Crittall style doors requires careful planning to ensure a successful outcome.

Design Choices

• Configuration: Decide between hinged doors, sliding doors (pocket or surface mounted), bi-fold doors, or fixed screens. Consider how the doors will operate and interact with your space.
• Glazing Bar Pattern: The grid pattern is a key design element. Common options include 3x3, 4x2, or custom designs. Think about how this pattern will complement your existing architecture and the views through the glass.
• Colour and Finish: While matt black is the classic choice, other dark greys (e.g., Anthracite Grey RAL 7016) are popular. Powder coating offers a durable and low-maintenance finish.
• Hardware: Handles and hinges should complement the industrial aesthetic. Black or brushed metallic finishes are common.

Installation and Structural Requirements

• Structural Integrity: For large external installations, especially with steel frames, the weight and structural loads must be carefully considered. Your installer or a structural engineer should assess the existing opening and advise on any necessary lintel or structural modifications.
• Accurate Measurements: Precision is key. Crittall style frames are custom-made, so accurate measurements are vital to ensure a perfect fit and proper operation.
• Professional Installation: Due to the technical nature of these products, particularly concerning thermal breaks, sealing, and alignment, professional installation by experienced fitters is highly recommended. Incorrect installation can compromise thermal performance, weather resistance, and security.
• Weatherproofing: For external doors, robust weatherproofing is essential. This includes proper flashing, sealing around the frame, and ensuring adequate drainage to prevent water ingress.

Maintenance and Longevity

Both steel and aluminium Crittall style doors are designed for longevity and require relatively low maintenance.

• Cleaning: Regular cleaning of the glass with standard glass cleaner and a soft cloth will keep them sparkling. The frames can be wiped down with a mild detergent and water to remove dirt and grime. Avoid abrasive cleaners or harsh chemicals that could damage the powder coating.
• Hardware: Periodically check hinges, locks, and handles for smooth operation. A light lubrication with a silicone spray can help maintain moving parts.
• Seals: Inspect rubber gaskets and seals annually for any signs of perishing, cracking, or shrinkage. Damaged seals can compromise thermal performance and weather resistance and should be replaced.
• Powder Coating: While highly durable, powder coating can be scratched or chipped. Minor damage can often be touched up with specialist paint, but significant damage may require professional repair to prevent corrosion (especially with steel).

With proper care, Crittall style doors can last for many decades, retaining their aesthetic appeal and functional performance.

Final Thoughts on Crittall Style Doors

Crittall style doors offer a compelling blend of historical charm, contemporary design, and practical benefits for UK homeowners. Their ability to maximise natural light, create a sense of openness, and add significant architectural interest makes them a popular choice for a wide range of projects, from period renovations to modern extensions.

When considering Crittall style glazing, remember to prioritise thermal performance (especially for external applications), ensure compliance with UK Building Regulations, and choose a reputable supplier and installer. Whether you opt for authentic steel or a high-quality aluminium alternative, these distinctive doors are an investment that can transform your home's aesthetic and functionality for years to come.

At Shard AG, we specialise in crafting bespoke Crittall style glazing solutions tailored to the unique requirements of UK homes. Our expertise ensures that every door and window not only captures the iconic aesthetic but also meets the highest standards of thermal efficiency, durability, and Building Regulations compliance. We work with both steel and advanced aluminium systems, offering a comprehensive design, manufacture, and installation service to bring your vision to life.