Natalie Young
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Crittall W20 windows, sold by Crittall as Corporate W20®, are the company’s classic external steel window. Slim rolled steel frames hold large panes of glass, so more of each opening is glass and less is frame. Steel glazing bars can divide the glass into the familiar Crittall grid, or the panes can be left clear.
Each window is made to measure by Crittall from 100% recycled steel. The frames are hot-dip galvanised against corrosion and finished in a Duralife® polyester powder coat, and Crittall gives the system a life expectancy of more than 60 years.
W20 keeps the slim profile of older steel windows, which is why Crittall describes it as ideal for listed and historic buildings. It suits conservation areas, period homes, shopfronts and offices, and sits just as well in a contemporary extension that wants genuine steel rather than a steel-look alternative.
We handle every stage: the first conversation, a site survey that takes in any conservation requirements, ordering from Crittall, installation and aftercare. If your project needs a published U-value for Building Regulations, such as a new build or extension, take a look at Crittall W20 TE windows too. We explain the difference further down this page.
W20 windows can be finished in any RAL or BS colour, or a custom shade. Popular choices include Crittall black, traffic grey, agate grey, light grey, white and pastel green. We used Crittall black (RAL 9005) on the Neptune showroom in Wimbledon. Crittall applies the Duralife® powder coat in the factory, so the frames need little more than an occasional clean.
W20 windows are double glazed and sealed with EPDM weatherseals. Crittall also offers solar control, self-cleaning and obscured glass, so you can choose privacy for a bathroom or solar control for a sunny elevation. On listed buildings, we can advise on a glazing bar layout that stays close to the original pattern.
Crittall's casement handles range from the Art Deco feel of the Deco and the traditional Berkeley to the cleaner lines of the Phoenix and Soho, with the Arched, Straight, Scroll and Curved designs completing the set. Handles pair with straight or curved peg stays or sliding stays. Top-hung windows that open outwards can use a single folding opener, which restricts the opening to about 100mm.
• Material: 100% recycled steel
• Corrosion protection: hot-dip galvanised to BS EN 1461
• Finish: Duralife® polyester powder coat in any RAL, BS or custom shade
• Life expectancy: more than 60 years
• Weather seals: dual EPDM weatherseals
• Water tightness and air permeability: 300 Pa
• Wind resistance: up to 1600 Pa
• Made under ISO 9001 and ISO 14001 management systems
Many of the buildings we work on still have their original steel windows. Before we recommend replacement, we check whether the frames can be restored, because conservation officers generally prefer repair where it is possible. Where replacement is the right call, W20 keeps the slim lines the building was designed with. On Wallis Road in London, a locally listed building that still had its pre-war Crittall windows, we installed Corporate W20 windows, externally bead glazed in Crittall black. Our guide to Crittall windows for listed buildings and conservation areas covers the consent process in more detail.
W20 has served commercial buildings for decades, from shopfronts to offices and former industrial premises. For Neptune’s showroom in Wimbledon, an early 20th century building over three storeys, we supplied and installed Corporate W20 windows and doors in Crittall black. See our commercial services for how we handle larger schemes.
It starts with a conversation about your building and what you want from it. We then assess the site, including any conservation area requirements, and help you choose the layout, colour, glass and hardware. Crittall makes your windows to measure, our team installs them, and we stay on hand afterwards for maintenance and genuine Crittall parts.
Straight answers to the questions we are asked most about Corporate W20 windows.
Contact UsBoth have Crittall's slim steel look. W20 is the established system, which Crittall describes as ideal for listed and historic buildings. W20 TE is the thermally enhanced version, with a published U-value of 1.4 W/m²K, so it is the one to choose when your project needs a U-value for Building Regulations. You can see both side by side in our Harlow showroom.
Often, yes. W20 keeps the slim profile of older steel windows, which is why Crittall recommends it for listed and historic buildings. Replacing windows on a listed building usually needs listed building consent, and conservation areas can have their own rules, so your local authority has the final say. Our site survey and design stage take those requirements into account from the start.
Yes. Corporate W20 windows are double glazed, with EPDM weatherseals to keep out draughts and rain. If you want the W20 look with a published U-value, ask us about W20 TE. Our guide, Are Crittall Windows Double Glazed?, explains more.
In many cases, yes. If your existing steel windows are beyond repair, W20 is a common replacement because it keeps their slim lines. If they can be saved, restoration may be the better route, and we do both. We will assess the windows honestly before recommending either.
Every W20 window is made to measure, so the price depends on size, opening type, glazing, colour, hardware and the installation itself. Our Crittall windows pricing guide explains what affects the cost, and we are happy to quote for your project.
Every W20 window is made to order by Crittall, so there is a manufacturing lead time before installation. We confirm the expected timescale with your quote.
Very little. Galvanising and the Duralife® powder coat protect the steel, so an occasional clean is usually all the frames need. If a handle, stay or hinge needs attention later on, our service and maintenance team can help, and we supply genuine Crittall parts.
Yes. W20 windows are on display at our showroom at Units 13-15 Stort Mill, Harlow, CM20 2SN, alongside W20 TE and HomeLight. We are open Monday to Friday, 7.30am to 4pm.



