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Aluminium Casement Windows

ALUMINIUM CASEMENT WINDOWS

Klosen / Aluminium Windows / Aluminium Casement Windows

Triple Glazed Aluminium Windows

ALUMINIUM CASEMENT WINDOWS

Stunning to look at, durable and offering near-unbroken views out (and plenty of natural light in), aluminium slimline casement windows are thoroughly modern and effortlessly stylish. Whether you’re building a new property or want to modernise an older one, these minimalist, flush-fit windows are hard to beat.

Like all our aluminium windows and doors, our casement windows are engineered to last and installed by an experienced team of specialist technicians. No matter how complex or unique your project is, we can carry out a top-tier installation that will last for years to come.

Download a brochure to explore the range of products we can offer or request your free quotation.

What Are Slimline Casement Windows

Slimline casement windows are the UK’s most popular type. Typically side-hung (although top-hung versions are available), they can be fitted in a whole host of different configurations, making them extraordinarily versatile.

We can supply both double and triple-glazed panels, meaning you don’t have to compromise on thermal efficiency either. Learn more about the windows we supply below.

Why Choose Slimline Aluminium Casement Windows?

Aluminium casement windows share the same benefits as regular aluminium windows (think durability, security and energy efficiency) but utilise a flush-fitting, ultra-modern design. These windows offer:

  • Sleek Aesthetics: If you want your property to look sleek and refined, these minimalist windows will certainly help you achieve that: you won’t believe what a difference they can make.
  • Excellent Ventilation: Casement windows open fully, inviting maximum airflow and ventilation into the property.
  • Weather Resistance: Slimline casement windows are engineered to withstand multiple weather conditions such as wind and rain.
  • Exceptional Durability: Aluminium is resistant to corrosion, rot and rust, ensuring long-lasting and high performance.

We’ve installed aluminium casement windows in properties across the UK, both for businesses and residential customers. From new builds to historic homes, our windows can transform the look of your property.

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Our Customer Reviews

Great Price & Quick Delivery

★★★★★
This company have been amazing and came to our rescue when another company let us down repeatedly over a period of 4 months during our building work. We got a great price, a quick delivery time and the same product but this time with lovely fitters who knew exactly what they were doing. Now we will will have a warm house for christmas HOORAY !! We went for 3 large sliding doors and the quality of the product is excellent . Many thanks to Audrey Cieran and the team I would recommend highly
- Esther Young

Delighted

★★★★★
Delighted with the product and the service provided by Klosen. The installation team were excellent and very helpful.
- Sara Hyem

Very Happy

★★★★★
We’ve been very happy with the work Klosen recently completed for us. They installed a variety of windows and sliding doors for us on our new build project. All of the information we requested early on was provided promptly and they were great with our architect. Very happy with the end result and the colour they helped us chose.
- Sarah Munton

Brands We Work With

We’re not prepared to settle for anything less than the best here at Klosen. That’s why we only supply slimline casement windows from Senior Architectural Systems and Cortizo, two of the industry’s leading brands.

Both companies are relentless in their pursuit of ultimate thermal efficiency, security, durability and – of course – aesthetics. Rigorously engineered and tested, the windows we supply come with lengthy guarantees and are offered in a range of finishes. Whatever your requirements, we’re confident we’ll have just the right product for you.

Download a brochure today to learn more about the windows we supply.

Cortizo logo
Senior Architechtural Systems Logo

Cortizo

Since 1972, Spanish company Cortizo has been leading the way in the manufacture of aluminium windows and doors. Working exclusively with aluminium, Cortizo has established itself as one of the industry’s major players.

All of its products are built to last, and all have been designed to beautifully combine function and form: in terms of aesthetics, very little else can come close.

We have improved many properties across the UK with quality Cortizo windows and doors. Our work in Skidby, Peterborough demonstrates how slimline aluminium glazing has been successfully incorporated into modern architecture, improving the property’s atmosphere and functionality by maximising natural light.

As well as that, our team also used Cortizo slimline casement window solutions to enhance Lowgate in Lincolnshire. A decision was made to replace old uPVC doors and windows with new aluminium ones to improve the appearance and functionality of the property.

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Cortizo Specifications

Transmittance: Uw ≥ 1.0 (W/m2K)

Acoustic insulation: Rw up to 45 dB

Air permeability: Class 4

Water tightness: Class E1200

Wind resistance: Class CE 2400

Security test: PAS24 passed

10 Year Guarantee

We offer a 10 year guarantee on all aluminium profiles and 25 years for the powder coating element

Thermal Efficiency

Stay warm in the winter and cool in the summer whilst cutting down on energy bills

Complete Flexibility

Our team are flexible throughout the entire process, including the design and installation of windows

25+ Years Experience

Klosen have over 25 years experience working with designers, architects and homeowners

Senior Architectural Systems

 

British manufacturer Senior Architectural Systems (SAS) has been around since 1991, and has risen to prominence as one of the nation’s largest and most well-respected suppliers of double and triple-glazed aluminium windows.

Consistently innovating and improving upon its products, SAS is known for its commitment to durability and thermal efficiency. The expanded polyurethane thermal barrier in its aluminium windows gives them exemplary thermal performance and water resistance.

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double fronted house with feature stonework and driveway

Senior Architectural Systems Specifications

Typical sizes:
Width (mm)
1500

Height (mm)
x 1500

Glazing:
Thickness: 28mm – 50mm

Air Permeability: 600 Pa
Water Tightness: 600 Pa
Wind Resistance: 2400 Pa

Residential CEN Standard:
1230 x 1480:
U-values as low as 0.73 W/m2K

Tested to PAS24, BS6375-2 and BS6375-3

Typical sizes:
Width (mm)
1400

Height (mm)
x 1400

Glazing:
Thickness: 28mm – 44mm

Air Permeability: 600 Pa
Water Tightness: 600 Pa
Wind Resistance: 1600 Pa

Residential CEN Standard:
28mm Double Glazed Unit, 44mm Triple Glazed Unit
1230 x 1480:
1.5 W/m2K 1.1 W/m2K

Tested to PAS24, BS6375-1, BS6375-2 and BS6375-3

Why Choose Klosen?

Klosen brings over 25 years of experience to every project, ensuring that our clients receive the highest level of expertise and craftsmanship. With a solid five-star reputation, we are committed to delivering exceptional results, no matter the size or complexity of the project. We offer a standard 10-year guarantee on all our work, providing peace of mind and confidence in the quality and longevity of the services we provide.

Our team has a proven track record of working on prestigious, high-profile projects, including a stunning Grand Designs home and the iconic ABBA Arena in London. This experience has honed our skills and reinforced our ability to deliver on time, within budget, and to the highest standards, making Klosen a trusted choice for all your construction needs.

AS SEEN IN

We’re proud to have supplied and installed Cortizo casement windows for a Grand Designs project in South Lincolnshire back in January of 2021. This stunning home was modelled on a historic Dutch barn but looks thoroughly modern – thanks in part to those contemporary and cutting-edge windows.

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Areas We Cover

Based in Market Deeping, Lincolnshire, we serve the entirety of Cambridgeshire and Lincolnshire, as well as London and the surrounding areas. Generally, we cover areas within a 60-mile radius of our base. Locations we frequently visit include Peterborough, Bourne, Stamford and Huntingdon.

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FAQs

What are slimline casement windows?

Slimline casement windows are a type of window that features narrower frames and profiles compared to traditional casement windows. This design maximises the glass area, allowing for more natural light and a cleaner, more modern aesthetic.

How expensive are slimline aluminium casement windows?

Although aluminium casement windows are pricier than the PVC or wooden equivalent, they are more durable and secure – not to mention more modern-looking. Prices vary depending on the size of the window and the finish you opt for, so please get in touch with us for an estimate.

How secure are the windows you supply?

Both our Cortizo and Senior Architectural Systems windows are very secure, having passed stringent PAS24 certification tests.

What colours and finishes are available?

A range of finishes can be specified, including optional powder coating finishes in any custom RAL colour – there’s guaranteed to be a shade that suits your property!

Get in touch with us today to receive your free quotation!