Clement Brooking Range of Steel Windows

Product Summary

Developed in collaboration with the Hampstead Garden Suburb Trust and other conservation bodies, the Brooking range of windows takes its name from the Founder of The Brooking National Collection, Charles Brooking, an internationally renowned collector, conservationist and architectural historian with whom the Clement Windows Group has had a long association. The Brooking National Collection is a broad collection of period British windows, doors and other associated historic detailing.

Providing a traditional appearance, these windows are specifically for use in very sensitive fenestration projects.

Manufacturing Specification

Made to suit your individual requirements Brooking windows are generally manufactured in accordance with BS 6510:2010 specifications for hot rolled steel windows. The mild steel sections used for Clement window and door frames are precision rolled in Switzerland using recycled steel to suit Clement’s unique profiles and tolerances. All frames and ancillary profiles are hot dip galvanised to BS EN ISO 1461 and available with a factory applied polyester powder coating, well exceeding the minimum paint thickness called for by BS EN ISO 13438.

Manufacturing Description

Frames are manufactured from hot rolled mild steel profiles with corner joints mitred, welded and dressed square and flat. Small panes can be formed with T glazing bars whose ends are tenon riveted and/or welded to the frame and cross joints are interlocked and welded with rigid joints. Composite windows can be assembled by connecting windows horizontally and/or vertically with mullions and/or transoms of hot rolled slim steel profiles. Box sections are available as tubes or as box mullions which can be either hot rolled or manufactured from sheet steel. Pressed metal cills are available in a choice of profiles. Trickle vents can be fitted in accordance with Part F of the Building Regulations.

Locking system

The Brooking range of windows is available with traditional single point locking and other security devices if required.


Brooking windows can be fitted into timber subframes, or fixed direct to brickwork, concrete or stone. Windows are fixed either direct or with fixing lugs using stainless steel screws that are appropriate to the structural opening.


Brooking can be supplied with various glazing options, from both inside or outside including:

  • Silicone fronting to simulate traditional putty.
  • Clear glazing.
  • Traditional T bars.
  • Double glazing.
  • Real, hand crafted, single glazed leaded lights.
  • Double glazed simulated leaded lights. Using genuine lead. A 16mm insulated glass unit offering an 8mm cavity, krypton gas filled.

Combinations of fixed lights, top hung, side hung and bottom hung windows are available as well as single and double doors in both ‘open in’ and ‘open out’ configurations.

Brooking windows accommodate single and insulating glass units of 16mm. These GGF approved windows are recognised and specified by many local and national conservation bodies.

In accordance with Glass & Glazing Federation best practice, Clement steel windows are generally factory glazed, however, our concealed fixings mean that fixed light windows need to be glazed on site after the frames have been installed. Metal glazing beads are optional and provided colour coded to match the frame. 

Brooking windows can be supplied with semi, round or gothic style heads, and ‘curved on plan’.

Dimensions (Provided for guidance purposes only)

Nominal profile width 25mm
Typical sight lines: fixed lights perimeter: < 37mm
Hinged casements: < 52mm

Windows and doors for composite panels are purpose made, generally within the limits shown in the table below; sizes outside these limits may be discussed with one of our sales consultants.

  Width Height Perimeter
WINDOWS Min (mm) Max (mm) Min (mm) Max (mm) Max (mm)
Fixed light 300 1800 300 1800 7200
Top hung 300 1800 300 1300 4800
Side hung 300 600 300 1300 3800
Bottom hung 300 1200 300 1200 4800
Single 600 900 2000 2100 6000
Double 900 1200 2000 2100 6600


The average Sound Reduction Index (SRI) of a single glazed unit is approximately 30 dB, but this varies with window type, size and glass thickness.

BS 6375-1:1989

Air permeability was measured in terms of opening joint length (m³/h/m) against progressively increasing test pressures through 200Pa (class A), 300Pa (class B) up to 600Pa (class C). Class B, or a maximum value at 300Pa of about 16 m³/h/m, was the UK standard requirement. Water tightness was measured in resistance to leakage at progressively increasing test pressures, 300Pa being considered the most severe UK requirement. Wind load resistance entailed deflection and gusting tests at pressures ranging from 1200Pa to 2400Pa.

 Window Type BS 6375-1 Test Pressure Class 1989 edition
  Air Water Wind BS 6375-1 Exposure Category
Fixed light 600 300 2400 2400
Top hung 300 200 2000 2000
Side hung (open out) 300 200 2000 2000
Bottom hung 200 100 1600 1200

Source: Steel Window Association


Clement Steel Windows Glazing


We offer five different styles of glazing, from clear glass, to genuine lead in an arrangement to match the pattern of your original leaded lights, to the G+ and Fenestra joint systems which are unique to Clement. All of these options have superb features which faithfully replicate those of original steel windows.

Clement Steel Windows Colours


Our steel windows are hot dip galvanized and available in a choice of highly durable Akzo Nobel powder paint colours. Clement Windows provide an average paint coating in excess of 100 microns on flat surfaces – the industry standard calls for 60/70 microns. Order from a wide range of RAL colours to match your scheme or choose different colours for the inside and outside of your windows.

Clement Windows Accessories


Browse a select range of accessories which perfectly complement our stunning steel windows, doors and screens. Carefully crafted in a number of different styles and available in a choice of colours and finishes, our range of handles and other fittings are made from the finest quality materials and manufactured with the latest technology in mind.