Aluminium Windows


Tilt before Turn aluminium window

Simply stunning aluminium window


The Dualframe 75 Si Tilt-before-Turn aluminium window uses advanced polyamide thermal break technology to provide thermal performance without the need to resort to complex and costly sealed unit specification. 

The Dualframe 75 Si Tilt-before-Turn aluminium windows are the ideal solution for high-rise or commercial applications, combining ventilation with large span openings and easy cleaning facilities. 

The specialised profile range adds great flexibility when constructing windows where inward and outward-facing rebates have to be combined, without the need and expense of coupling sections or dummy frame to fixed lights. Universal frames can be used to create the most complex of screens easily combining casement, tilt before turn, and reversible opening lights, as well as inside and outside glazing. Combined with the option of having different finishes inside and out, the Si suite will give you endless choices.

System features of the Dualframe 75 Si Tilt before Turn aluminium window: 

  • Unique operation action to minimise risk of injury to operator or damage to the product 
    • Handle is key operated and must be inserted to access the turn mode
    • Once window is closed, it will automatically default to the tilt only mode
  • Tailed gaskets and centre seal reduces thermal radiation with no foam inserts needed
  • External beading requires no additional components to comply with BS7950
  • Superior thermal performance is achieved with a unique polyamide thermal barrier

Design features of the Dualframe 75 Si Tilt-before-Turn aluminium window: 

  • Concealed hinges, flush vents and a flat profile ensures a simple, streamlined aesthetic and prevents a clash with plaster lines
  • 88mm sightline maximises viewing area and increases incoming natural light - all without compromising the U-value of this window system

Our brochure is available to download on the documentation tab above.

Book on our Product Introduction Training online.

Dualframe 75 Si Brochure (pdf)

Product benefits


  • 24mm, 28mm, 32mm as standard
  • Vent weight up to 100kg
  • Glazing thickness up to 47mm


  • Tilt-before-Turn and fixed lights available including frame couplers and curtain wall interface
  • Key-operated handle, with turn mode only with key inserted, minimises risk of user-injury and product damage
  • Secured by Design Accredited


  • Dual-colour finish available allowing for flexibility in internal and external design
  • Concealed hinges within the frame removing colour matching issues
  • 88mm sightlines maximises viewing area and incoming natural light


  • Thermal Performance - A++ BFRC(UK) rating
  • Water Tightness - 600Pa
  • Air Permeability - 600Pa
  • Wind Resistance - 2400Pa

More information


Projects using aluminium windows DUALFRAME 75 SI

Silverstone Experience, Northamptonshire

United Kingdom
TECHNAL’s curtain walling and Stormframe STII aluminium doors have been used to create an impressive, light-filled entrance to the state of the art Silverstone Experience building.

Ysgol Penyffordd, Wales

United Kingdom
Selected for their weather, thermal and security performance, TECHNAL aluminium curtain walling, windows and doors was specified and installed at Ysgol Penyfford - a £7 million-pound primary school located in the Flintshire villlage of Penyfford in Wales. This project has been constructed to BREEAM Excellent standards.

Stapleton House, London

United Kingdom

Stapleton House is a design and build project by Balfour Beatty Construction Services who created 862 high specification student spaces across nine floors in the large and logistically challenging student accomodation project in North London. 

The property is located by the very busy Holloway Road and therefore needed an enhanced acoustic rating for each elevation facing the public highway, as well as the achievment of high thermal, weather and security standard throughout. 

The fabricator Sealtite, along with the Technal UK technical support team duly delivered a proposal of Elegance 52 curtain walling and the Dualframe 75 Si windows and provided detailed drawings, strength calculations, thermal calculations and information on acoustic testing. 


Menai Science Park

United Kingdom
Located in Anglesey and operated by Bangor University, Menai Science Park is the flagship building for Wales' first dedicated science park.

Eastside Locks, Birmingham

United Kingdom

Eastside Locks is a 17-storey student accomodation block located in the heart of Birmingham. High-performance windows and doors from Technal have been incorporated into the off-site, modular design. 

This £30 million construction at No. 1 City Locks is on what was a brownfield site alongside the Digbeth Branch Canal and forms part of the city's long-awaited Eastside Regeneration Project. Working in co-operation with Sisk Construction, Glenn Howells Architects and Elite Aluminium Systems Ltd, Technal won this project by 'value engineering' the original curtain wall design. 

By re-evaluating the project's technical, logistical and budgetry challenges, a Dualframe 75Si window wall specification provides a cost-effective solution which could be pre-fitted into the precast concrete modules that make up the building's elevations. This solution also enables any replacement glazing and maintenance to be done from inside, which isn't possible when using conventional curtain walling. This project also features the use of Technal Elegance 52 ST curtain walling to enclose the stair towers, and STII thermally broken commercial doors for main access routes.   


Project Architect David Hickman commented: “We are really pleased with the building overall, while the windows work really well both in terms of their colour and their proportions in the tower. We opted to go for the full height frames which means as soon as you enter into the student rooms they give a really good connection between the inside and outside of the building; and great views over the city.

“We have worked with Technal previously, including the student and wider residential market. In this instance the idea of a modular solution and installing the Dualframe assemblies at the precast plant evolved during the tender submission process, and proved very effective.”

University of Birmingham School, Birmingham

United Kingdom

The University of Birmingham School was the first academy free secondary school to be assigned to a particular university. This is a new model of education, bringing together the best of university research and teaching with best practice in secondary education. 

The school's success was supported by the university's estates team and the school's preopening team working closely with the Interim Director of Operations for the school. Wilmott Dixon, TECHNAL UK and Associated Architects also collaborated to ensure a high standard of building design to complement the equally high teaching methods. As a result, the school has been used as a standard since opening in 2015.

TECHNAL Dualframe 75 Si Casement windows were specified for this project in a 210mm high module to achieve the required available air flow and light transmission. This is the ideal solution for education, healthcare and commerical applications due to the combination of good ventilation with practical features like easy operation and large span openings (with separate safety restrictors) all whilst remaining cost-effective. 

Stormframe STII Commercial Doors were specified to achieve robustness and increased thermal insulation. Elegance 52 ST Curtain Walling was also used to deliver more natural light into the project without sacrificing weather performance, thermal insulation and ease of fabrication. 

Dean Sherwood, Project Consultant at TECHNAL commented on his involvement saying, "With pupils and teachers in mind, it was important to acheive robust and safe operation and the anti-finger trap stiles and stronger profiles do this whilst maintaining elegant design."