Reynaers SL38 Suite of slimline aluminium windows

Reynaers have for a while offered their excellent suite of aluminium windows. One of these was the CS38.

This has now been upgraded to the new Slim Line 38 series. It offers better performance than ever before.

SL 38 and SL 38-HI are now available and offer ultra slim profiles and improved market-leading energy efficiency.

What is the SL38 suite of windows from Reynaers?

The iconic Nedinsco building now features Reynaers windows being refurbished to apartments, retail units and a TV Studio.
The iconic Nedinsco building now features Reynaers windows being refurbished to apartments, retail units and a TV Studio.

The new improved system offers even better thermal insulation. This is coupled with a slimline appearance to give the look of original slain steel windows.

Close examination of the profiles shows an aluminium window with all the aesthetics of a steel window.

The range of outer frame profiles available make this Reynaers SL 38 ideal for the replacement of old windows or to new build openings.

There are three unique designed available giving consumers and the trade real choice in what window suits which property better.

Three outer frame and vent combinations with Reynaers

The three variants possible are Classic, Cubic and Ferro. Regardless of which system is chosen, one of the best design features is the lack of draining caps.

Aluminium windows are often face drained to facilitate the drainage of water to the outside. On the Reynaers windows an invisible drainage system has been designed into the system. This avoids the sometimes unsightly presence of drainage caps on the bottom rails of the windows.

Each of the three variants, Classic Cubic and Ferro offer very similar sight lines. The overall frame dimension for each on an outward opening window is 56.5mm.

The Classic systems is a more traditional looking window. At the bottom of each vent and outer frame is a loping section very much like a weather bar. But this does not detract from the contemporary lines and slim aluminium profiles.

The Cubic variant of the Reynaers window is a much more flatline in appearance window. This we think is the best looking of the three products.

The Ferro we think is designed to replicate the old W series Crittall Windows. At the bottom of the vent is a projecting ‘bar’ section typical of windows such as the old W20. The outer frame like the Cubic remains flat in profile.

One clever feature of the system is that a special modification is possible enabling the window to be provided with hidden hinges.

Hidden hinges are commonplace on products such as a Schuco door so we presume this relates to the hinges visible on the tilt and turn variants rather than the casements.

Specifications of the Reynaers SL 38 Windows.

All features a highly insulated three-chamber system. You can choose from an outward opening casement with the classic variant as well as tilt and turn or turn and tilt options with Ferro and Cubic.

U values of 1.4 W/m²K or more depending on the glass option and window configuration is possible. The system will accept double or triple gazing of up 55mm.

Weather performance as you would expect from a modern aluminium window is on a par with other good systems. The windows will achieve air tightness of Class 4 (600Pa) and water tightness Class 9A (600Pa).

The Reynaers window gives choice for steel replacement windows in aluminium.

It is evident from the design of the window that it is targeted at the popular steel window replacement market. Old buildings featuring steel windows, central London properties, warehouses and any industrial urban type building would certainly benefit from these new windows.

But it is clearly ideal for new builds and any project requirement for an ultra slim and contemporary aluminium window.

If you would like further information on the Reynaers windows or steel replacement windows in aluminium generally, please contact us.

Images courtesy or Reynaers.

Published on January 20, 2016

Reader Interactions


  1. Jenna says

    Hi there,

    We’re looking at buying a set of aluminium windows for our new build (modern Georgian style) over in North Lincolnshire.

    We have 6 sets of Juliette windows at the front of the house (1000mm wide), and 2 sets of French doors.
    Do you think the Raynaers SL38 is the best option to achieve the slimmest frame and mullion for the Juliette windows and French doors? As the Juliette windows aren’t that wide, we want to have as much glass pane as possible.

    Many thanks,

    • Nick Dardalis says

      Hi Jenna, thanks for your question.

      The Reynaers SL38 is an excellent window system and comes with a great choice of frame options to give you the look you want. Generally most window mullions are similar sizes and the frame/mullion combination also depends on the frame size needed for your installation. As it’s a new build you should be able to have the slimmer frame Reynaers offer compared to replacing old windows with new that often need a thicker frame.

      It’s hard to advise you exactly on this one but a good Reynaers fabricator should be able to help you. I can suggest speaking with the below

      Vista Frames
      Unity House
      Rotterdam Road
      North Humberside
      HU7 0XD
      Tel: 01482 307307
      Website :

      Rohaus Living Systems
      Douglas House
      Leons Way
      Tollgate Industrial Estate
      ST16 3EE
      Tel: 01785 242357
      Website :

      Altitude Aluminium
      Access House
      Aviation Park
      Flint Road
      CH4 0GZ
      Tel: 01244 529 199
      Website :

      Hope this helps
      Kind regards

  2. Matt Mitchell says


    I’m looking for excellent local tradesmen who can supply and fit top branded aluminium windows and doors in the Noethwich, Cheshire area.


  3. peter says


    I’m looking for some aluminium Crittall style windows and french windows for a Dutch barn conversion. Any suggestions and contacts appreciated.