ASWS involved in restoration of historically significant North London mansion


Coming under the jurisdiction of a highly respected neighbourhood heritage body, the comprehensive restoration and limited remodelling of a very large residential property in North-West London has posed substantial challenges for all parties involved, particularly those responsible for the Grade I listed exterior envelope.

As a result, the heritage architects and highly experienced main contractor called on the expertise of Associated Steel Window Services (ASWS) to conduct a comprehensive condition survey and compile reports for the conservation authorities involved. This was prior to the London-based metal window specialist eventually being awarded contact for the full off-site refurbishment of 56 large scale multi light, leaded light, mid universal steel windows and the associated timber subframe works.
Overlooking one of the capital’s most popular parks - famous for its woodland walks as well as the vibrancy of its local community – the project had to adhere to very strict guidelines on the authenticity of the building methods used for restoring the century old fenestration. This included having to agree on the scope of the repair work to the frames themselves in advance, as well as sourcing visually matching ‘hand blown’ glass.
The Contract Director for ASWS, Kris Bennell, recounted, “A property of this status would have originally had extensive servants’ quarters, and apparently previously featured a pool room, but its state of decay meant it had to be completely gutted out to a shell with no roof. Following on from our precontract survey and detailed submissions with drawings, we were awarded the contract to restore all of the windows, with permission obtained to carry out the main repairs back at our workshops.”
“The windows on the second floor were in an especially poor condition, due to exposure to the weather, with corrosion of the steel having caused many of the individual small glass panes to have blown, while the bottom rails and other sections had to be replaced. This work, along with the way we spliced in new sections of timber into the sub-frames, had to be overseen by Heritage England as well as the Trust, while the original leaded light glazing was replaced with 4mm hand drawn glass set in 16mm lead cames which are much slimmer than the conventional ones used now.”
While some of the less serious pitting in the frames was skilfully filled or burnished out, ASWS’s craftsmen also removed, stripped and repolished all of the brass hardware fitted to the 56 windows. They further restored a very large oak door forming the main entrance. The reinstatement of the period steel windows and subframes, along with final decoration was completed some 18 months after ASWS first began work on site, once the building had been reroofed and much of the other work had been carried out.
Kris Bennell concluded, “This is one of the largest individual residential properties we have ever been involved with and presented a number of technical challenges, including the meticulous cataloguing and storage of all the component parts crucial to the authenticity of the outcome. We are proud to see this substantial home now fully restored and looking so good.”
ASWS is a long-established member of the Steel Window Association and well recognised expert in the repair of metal windows, from the earliest wrought iron examples through to contemporary curtain walling. The family run business is frequently called upon to prepare condition surveys during the appraisal stages of a project, which then become part of the planning or listed building permission process. The company also maintains a very large stock of ironmongery and metal frame components to assist in its restoration work.  
Pictured is Kris Bennell, Director for ASWS.

For more information on ASWS, please visit



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