Conversion of the Grade II* listed former Patent Office in London’s Chancery Lane Conservation Area makes extensive use of traditional solid timber panelled doors from specialist manufacturer Longden, some incorporating innovative concealed overhead closers.

The Patent Office building developed over more than fifty years, starting in the mid-nineteenth century, in an ad-hoc way but resulting in a building of considerable architectural and historical significance. This includes the magnificent galleried and barrel-vaulted library within Sir John Taylor’s 1902 Southampton Building. The 100, 000 ft2 complex has been extensively refurbished and extended for commercial use for developer City and General by contractor Wallis with architects Sidell Gibson Partnership.

Longden supplied over 140 panelled doors to replace older and damaged ones and, in many cases, to provide 30-minutes fire resistance as well as good sound reduction characteristics. Some doors incorporated overhead door closers with the mechanism concealed within the jamb at the top of the door leaf.  This innovative approach avoids visually intrusive surface-mounted closers and invasive work to floors to fit floor-level closers. Where needed, replacement reveal panelling and door frames were also supplied.

Longden doors and doorsets are traditionally constructed with solid timber stiles, rails and panels. All main joints are through mortice and tenon types, and wedged using waterproof adhesive for maximum durability. Independent certification under the BWF-CERTIFIRE scheme ensures that fire performance of all doorsets meets design requirements when installed.  At the Patent Office, doors and doorsets were manufactured from American White Oak and Tulipwood for painting, in various 2, 3, 4 and 5-panel styles to match the original doors. Flat panels typical of the period were highlighted with bed moulds and bolection mouldings, and some doors are partially glazed. The Longden range also offers raised and fielded panels, moulded framings in different styles, various configurations that can include glazing and a wide choice of applied mouldings. Production techniques unique to LS Longden enable traditionally crafted doors to achieve performance levels such as 60-minutes fire resistance and 35 RwdB sound reduction where needed.