Façade systems from architectural aluminium specialist, Technal, have been specified by Boyes Rees Architects as part of the major refurbishment of Royal Mail’s flagship Mount Pleasant Mail Centre in London – one of the world’s largest mail sorting offices.


The project involved the refurbishment of the ‘Letter Office Building’ located at the boundary of the London Boroughs of Islington and Camden.  The building, which dates back to the 1930s, was in need of extensive façade repairs and upgrading works to improve energy efficiency and to create a distinctive façade which would sustain and enhance this historic landmark. 


Originally built on the site of Coldbath Fields Prison, Mount Pleasant is now Royal Mail’s busiest central London sorting office, which sorts and despatches over 1m items of mail across the city every day. The facility is part of a site which covers an area of 12 acres and is the centre of a network of 23 miles of tunnels, 70 feet under the streets of London, that were once used to distribute mail. 


During the refurbishment, the sorting office had to remain fully operational 24 hours a day. The building was stripped back to its original concrete walls; white monolithic render was renewed, and upvc windows were replaced with high performance aluminium curtain walling from Technal.


Technal worked closely with Boyes Rees Architects and specialist fabricator Glassolutions Installation to develop and implement the specification for the curtain walling.  The slim profiles of the GEODE-MX Visible Grid system met the architects’ requirements for maximising natural light and retaining the building’s character.


Technal’s curtain walling was used for all elevations with the largest glazed unit spanning up to 1.7m.  Mechanically-actuated top hung concealed vents were inserted into the façade for smoke control in the event of a fire, whilst maintaining a flush façade.  Commercial doors from Technal were also specified to provide access at various points around the building.


Commenting on the glazing specification, the Project Architect, Eric McLennan, Associate at Boyes Rees Architects, said, “This project was particularly challenging because the sorting office had to remain in use throughout.  Our aim was to create panels of flush glazing with a smooth frame and slim sight lines.  Having used Technal's systems on other projects, we were confident that they could successfully realise our design for the glazing and cost effectively.”

“Technal provided us with a range of systems that met our specification criteria and we are very pleased with the finished result.  We wouldn’t hesitate to use their façade systems on future schemes.”


The curtain walling was polyester powder coated in dual colours – white internally and bronze externally to contrast with the white render and echo the appearance of the original windows.  The curtain walling was glazed in clear low E high performance solar control glass to further improve the building’s energy efficiency.


Technal’s GEODE-MX Visible Grid system can be used to create flat or faceted façades up to 20° and can accommodate large spans of 6mm to 32mm glazing.  It is engineered for excellent thermal performance and will achieve low U values.  Its slim, constant 52mm sight lines for the mullions and transoms give a uniform appearance across the GEODE suite.  Other options include concealed vents for natural ventilation whilst maintaining an uninterrupted flat façade; GEODE-MX Trame for horizontal or vertical emphasis, and structural, beaded, acoustic and sloped glazing.


For further information about GEODE-MX curtain walling and other Technal façade products, call 01 410 5766, email or visit