Propak’s innovative thermally broken steel system has been well received by many major architects and is now used extensively in high end residential and refurbishment projects throughout UK.
We have worked on behalf of some of the largest developers and property owners such as The Crown Estate and are now the largest UK based fabricator of the slimline system. We have a wealth of experience in design, manufacture and installation so can support you from initial design right through to completion.
The very narrow profiles provide an economic and aesthetically appealing solution for a wide range of window constructions with impressive face widths of just 25 or 40 mm. The steel and glass fibre construction guarantees minimal heat loss and maximum stability.
The profiles can give a sleek minimal frame for a modern building and for refurbishments to maintain an authentic, historical look to outside of the building whilst meeting the highest standards in terms of thermal and acoustic sound reduction; with practically no restrictions.
The conventional opening types for buildings from the 1950’s and 1960’s, such as inward or outward-opening side-hung, double vent, bottom-hung, top-hung or projected top hung windows, can be constructed from standard profiles.
Technical Specification
The systems that we manufacture can be designed to accommodate a wide range of specifications as shown in the tables below.
A large range of curved units and surface finish options are available to with all conventional opening types such as inward or outward-opening side-hung, double vent, bottom-hung, top-hung, projected top hung, pivot, or tilt and turn windows, can be constructed using standard profiles within the system.
Acoustic | Up to 47dB |
Thermal Properties | U-Values down to 0.8 W/m2K |
Maximum H | Heritage System: 1800mm |
Materials | Mild Steel |
Surface Finishes | PPC – Polyester Powder Coating – Standard & Non Standard RAL Colours |
Glazing Depths | Heritage System: 34mm |
Construction Types | Arched heads & bespoke geometrics |
Access Equipment Ironmongery | Hinges: Welded or Screw-on. PPC, steel or stainless steel |
Spread Technical Features | Arched heads and bespoke geometrics available |
Tests Certificates | Heritage CE marking details: HI System CE marking details: |

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