ASWS Executes Complex Fenestration Contracts As The Harrison Achieves Energy Targets

As an acknowledged industry expert in the repair and replacement of steel, timber and other fenestration types, Associated Steel Window Services (ASWS) was awarded four separate prestigious packages, as well as being tasked with additional project elements, during the conversion of a former furniture warehouse. The high-spec office spaces now afford the occupants contemporary standards of energy performance and amenity.

Pictured is The Harrison (formerly Curtain House), Shoreditch, London.  ASWS delivered expert restoration and replacement of steel and timber fenestration during its transformation into 40,000 sq. ft. of high-spec office space.

Formerly known as Curtain House, ambitious designs by the project architect, Anomaly, have seen the seven building Grade II listed 19^th century structure in London’s Shoreditch transformed into one 40,000 sq. ft. of flexible office space, spread across five floors; now renamed The Harrison.  A project for Aviva’s Climate Transition Fund, the two-year redevelopment by Red Construction is targeting BREEAM Excellent rating as well as achieving a top EPC Rating of ‘A’; to which the upgrading of the steel and timber fenestration proved critical.

The Operations Director for ASWS , Kris Bennell, commented: “We were asked to cost the replacement of the timber windows, the refurbished timber windows, the new steel windows and the refurbished steel window packages - being successful with all our tenders, based on our abilities as well as our competitive prices, combined with our previous experience at Hackney Town Hall with Senior Project Manager, Matt Coleman."

"Our proposal was attractive to them as it meant they would have one company and manager covering all the elements of the work rather than three or four different contractors on site, while it also offered them a continuity of finish across the project. “While it was planned to replace timber windows in one of the lightwells, the strategy changed to refurbishing them, so a dozen windows had new sections of timber spliced in where the rot was too bad or filled using our new resin repair technique; along with fitting new glazing bars and reglazing works. The opening vents were also overhauled and draught proofed.”

Addressing another aspect of how the specialist’s role evolved, Kris Bennell continued: “Once the scaffolding went up, we discovered that the timber sub-frames were in very poor condition – some of the wood being beyond resin repairs – with large sections or even the entire sill needing to be replaced. We matched all the profiles, the angles and other details of the sills so that the repairs blended in seamlessly. What made this much more difficult was that the steel frames could not be taken out, so the subframes had to be milled in three very slim sections that were then inserted through an extremely narrow slot and fixed together.” 

Where the building’s Mid Universal sections steel windows had suffered serious corrosion, the ASWS team welded in new sections which themselves had to be made up from lengths of steel plate as the authentic profiles are no longer available. Equally in need of action, the ironmongery was all demounted, stripped, polished and lacquered ready to be refitted as one of the final operations prior to handover.   

Issues such as party wall agreements held up the creation of a new rear entrance to the building, requiring ASWS to hold in storage the large new steel windows it had fabricated, so that their installation could be coordinated with the wider programme of works. As part of the upgrade to this area of the building, ASWS also refurbished 12 very large solid steel internal sliding doors and mechanisms which were being rehung. Though these heritage doors appear to be fully operational, they are in fact fixed shut to avoid the risk of opening such heavy units.   

ASWS carried out extensive internal fenestration works, including the refurbishment of timber and steel windows, reglazing nearly 350 panes, and restoring original sliding steel doors.

Glazing gains

ASWS undertook the extensive reglazing of nearly 350 panes of glass, with the use of authentic putty glazing requiring careful coordination with the decorating sub-contractor in order to allow sufficient curing time.  While every pane had to be measured for the production of perfectly shaped replacements, some of the retained windows saw their glazing uprated through the installation of specially produced slimline 4-4-4 IG units.  These offer a centre pane U-value of 2.6 W/m²K compared to a typical figure for existing single glazing of 6.4 W/m²K, giving a significant performance uplift, while the use of very narrow, 7mm warm edge spacer bars ensure they cannot be seen above the upstands.

The change of use to modern office space posed another aesthetic challenge as the creation of new washrooms, with the toilets being installed in front of windows. Although the occupants are shielded by internal cubicles, it would have meant pipework and ducting still being exposed to view from the outside through the windows. So, ASWS proposed to install multiple sections of film internally which effectively blacked out the glazing.

Matt Coleman, Senior Project Manager at Red Construction, comments: “The Harrison has been a fantastic project from start to finish; an iconic heritage building undergoing extensive and lasting retrofit that has left everyone involved feeling thrilled. Working with companies like ASWS, which prides themselves on a high standard of finish and has the expertise to undertake projects of this calibre, is always a pleasure. This is my second time working with ASWS on a large refurbishment project and their team, from the Directors to the site operatives, is fantastic to work with. They are experienced, skilled and always there to help push a project along. They are a team I would love to have on every project and their knowledge in the refurbishment sector is second to none.”

The Project Architect for Anomaly, Henry Dunford-Baker, reflected: “By improving the U-values and airtightness, a lot of the windows have become far more thermally efficient.  Without that there is a good chance those high standards wouldn’t have been reached, so by virtue of ASWS doing those works for us they’ve contributed to us achieving the BREEAM and other accreditations. Their standards were extremely high and the overall product has been exceptional. Working with windows of that age is no small undertaking and restoring them on site has meant the building has kept much of its original character.  If we had put in new fenestration rather than refurbing them, the building would look vastly different from what it does today – bringing those original windows back to life has had a very positive effect.”

Kris summed up ASWS’s involvement: “The Harrison demonstrates the breadth of skills that we can now bring to a project, having expanded our offer over the past four or five years to become a one-stop-shop for all things fenestration. The standards of insulation achieved here are also a fantastic element to this project which sets new standards. It was obviously a labour of love for Anomaly and it is a delight to work with people who want to restore the past – there was a real sense of bringing the building with us on the journey. We see a great future for construction in optimising heritage projects.  I believe The Harrison will come to be viewed as an exemplar of how to do retrofit.”

ASWS offers a full range of survey, repair, replica replacement and maintenance services for all ages and types of metal and timber windows.  For more information on ASWS, please visit asws.co.uk