W50 Thermally Broken

Energy efficient steel windows

With narrow sightlines and a U-value as low as 1.4 W/m2K, the W50 TB steel window is based on highly engineered, thermally broken steel sections designed to closely replicate the character of the traditional W20 steel window.

The design of the thermally broken profile means that W50 TB steel windows are manufactured differently from traditional solid, hot-rolled steel section windows.

Steel Window Services has introduced the W50 TB steel window to extend the range of solutions available to specifiers, especially in the new build sector where outstanding contemporary architecture is required.

Offering all the benefits traditionally associated with steel windows, including slender profiles, large panes of glass, good light transmission and large opening windows, the W50 TB provides incredible versatility.

  • All the benefits of traditional steel windows
  • Slender profiles, large panes of glass and good light transmission
  • Large opening windows
  • Ideal for outstanding contemporary architecture

W50 TB comprises the same forms, proportions and overlapping effects of the original 20th-century hot-rolled steel window profiles, refined by cold rolling technology. The innovative high-density polyurethane isolator used as a thermal barrier, together with the possibility of housing low emissivity glass up to 37 mm, allow them to fully respond to current regulations and contemporary needs for comfort, including in harsher weather conditions where windows made from solid steel profiles may not be sufficient. The range is completed by a wide range of exclusive fittings in several finishes, reproduced from original designs of the modern era. Any kind of inward or outward openings are possible.


  • Precision cold formed steel profiles of 1.5 mm thickness
  • Classic 'stepped-leg' design
  • Mechanically fixed rebate gaskets
  • Accommodates double and triple glazing up to 37 mm
  • High density cast in polyurethane isolator
  • Choice of different glazing beads
  • Compatible with 16 mm friction hinges
  • Available with a wide range of opening options

Windows and Doors made from Cold Rolled Steel profiles are pre-coated with a zinc rich primer and then coated with one of the many RAL colours by powder coating

An extensive range of colours is available (any standard RAL reference).

Prior to powder coating applications, all finished frames are shot blasted to SA2.5 in accordance with ISO 8501.1.

All windows are optionally coated to the British Standards to enhance their aesthetics and minimise future maintenance.

Standard specification finish:

Environmental Classification to C1 – C3.

  •  Shotblast to SA 2.5 in accordance with ISO 8501.1                                      
  • Zinc Rich Epoxy Primer 60 – 80 microns
  • Ultra-Durable Architectural Powder 60 – 80 microns


Enhanced specification finish:

External Environmental Classification C4 – C5

  • Shotblast to SA 2.5 in accordance with ISO 8501.1
  • Zinc Rich Epoxy Primer 60 – 80 microns
  • Epoxy primer 60 – 80 Microns
  • Ultra-Durable Architectural Powder 60 – 80 microns

The durability and high performance of steel windows can be enhanced even further if good maintenance practices are observed.

Frames should be cleaned at regular intervals using a mild, non-alkaline detergent in warm water, applied with a soft cloth or sponge.

Glazing and perimeter sealants should be inspected on an annual basis and appropriate maintenance action should be taken.

All hinges, pivots, handles, stays and other mechanical parts should be checked for operation, kept free of excessive paint build-up and lightly lubricated.

Full O & M Manuals (Operation and Maintenance Manuals) are supplied by West Leigh upon request on any new window project.


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