A Step By Step Guide To Specifying Crittall Windows
- August 21, 2025
- General
Crittall windows have been synonymous with quality steel frames since Francis Henry Crittall revolutionised fenestration in the early 20th century.
When it comes to specifying steel windows for your project, understanding the process is crucial for achieving the perfect balance of aesthetics, performance, and compliance.
This guide will walk you through everything you need to know about how to specify Crittall windows effectively, including:
- Choosing the right system for your project
- Customisation options for Crittall windows
- Our range of interior and exterior Crittall windows
Understanding Crittall window specifications
Initial assessment and planning
Before diving into specific measurements and technical details, it’s essential to assess your project’s requirements. Consider the building’s architectural style, whether it’s a heritage property requiring conservation compliance, or a modern build where contemporary steel windows can create striking Art Deco-inspired features.
Key factors to consider include:
- Building orientation and natural light requirements
- Local planning restrictions and building regulations
- Energy efficiency targets
- Security considerations
- Maintenance preferences
Taking accurate measurements
Precision is paramount when specifying Crittall windows. Steel frames require exact measurements to ensure proper fit and optimal performance. Professional surveyors typically measure:
- Overall opening dimensions (width and height)
- Wall thickness and reveal depths
- Structural opening tolerances
- Sill heights and head details
- Any architectural features that may impact installation
Crittall windows for any project
Residential applications
Crittall windows work beautifully across various residential settings, from period property renovations to new-build contemporary homes. The clean lines and slim profiles characteristic of steel frames create an abundance of natural light while maintaining structural integrity.
Popular residential applications include:
- Kitchen extensions with floor-to-ceiling glazing
- Internal screens dividing living spaces
- Traditional casement windows in conservation areas
- Modern interpretations featuring black steel windows
- Crittall internal doors for open-plan living
Commercial projects
The durability and longevity of steel windows make them ideal for commercial applications. From office buildings seeking maximum natural light to industrial conversions requiring authentic materials, Crittall products deliver both form and function.
Commercial benefits include:
- Low maintenance requirements
- Fire-rated options for safety compliance
- Sustainability credentials through recyclable materials
- Customisation options to meet specific needs
Are different glazing options available for Crittall windows?
At Lightfoot, our Crittall windows are available with various glazing options suit your needs. We offer glazing options to reduce noise, control solar gain and ensure privacy which include coloured, reeded and frosted glass. Today’s Crittall windows also incorporate glazing options that dramatically improve energy efficiency compared to single glazing.
What frame finishes and colours are available?
While black steel windows remain the most popular choice, modern Crittall products offer extensive colour options.
Available finishes include:
- Classic black (the most popular option)
- Bronze and heritage colours
- Contemporary RAL colours
- Dual-colour options (different internal/external finishes)
- Specialist finishes for marine or industrial environments
What are some common mistakes to avoid when specifying or installing Crittall windows?
Common mistakes when specifying Crittall windows includes:
- Inadequate measurements – steel frames require precise dimensions
- Ignoring building regulation thermal performance requirements
- Poor structural support planning for heavier steel frames
- Incorrect glazing specifications for the application
- Rushing installation – steel windows need careful, precise fitting
Working with experienced Crittall specialists avoids these costly errors.
Our Crittall range at Lightfoot Windows
At Lightfoot Windows, we offer the complete spectrum of timeless Crittall products, ensuring we can meet any project requirement. Crittall windows stand out from traditional steel or aluminium windows with their iconic slim sightlines and minimalist profiles, delivering a signature aesthetic that sets them apart in design. Our internal and external range of Crittall windows includes:
Homelight Range: Perfect for residential applications, offering excellent thermal performance with traditional aesthetics.
Corporate W20: Designed for commercial applications requiring enhanced performance.
W20 TE: Thermally enhanced option for projects demanding superior energy efficiency.
We also offer a range of Crittall steel doors to complement your project, alongside more specialist products such as:
- Internal screens for open-plan designs
- Bespoke windows tailored to unique architectural requirements
- Heritage-compliant options for listed buildings
Lightfoot Windows: Crittall specialists since 1935
As the largest and longest-running specialist partners in the Crittall network, Lightfoot Windows brings unparalleled expertise to every project. Since 1935, we’ve been perfecting our craftsmanship and expanding our knowledge of steel window specifications.
Our decades of experience mean we understand the nuances of specifying Crittall windows for every type of project, from small residential installations to large commercial developments.
From initial specification through to installation and aftercare, we provide complete project support, and our London showroom allows you to see our products before making decisions. You can also view our Gallery page to see examples of our Crittall window installations and find inspiration for your project.
Get expert guidance for your Crittall project
Contact us today to discuss your requirements and receive a free, no-obligation quote. You can reach us through our online contact form, call us on 020 8662 9090, or email general@lightfootwindows.co.uk.
Want to get a quick estimate on new Crittall windows? Simply visit our ‘Get An Estimate’ page and fill out the required information, and one of our friendly experts will get back to you within 48 hours.