The Drill Hall

CONTEMPORARY CONSERVATION & RETROFIT

At the end of an unassuming carriage way off Farringdon Road in a small courtyard is an impressive portico bearing the crest of the 2nd City of London Rifle Volunteer Corps and a plaque with the year 1888. A small door to the side takes you into a vast hall of parquet flooring bathed in light under a glass roof supported on steel trusses spanning 16 metres on decorative brick arch walls. This is their Drill Hall, originally home to the local regiment made up predominantly of printers, then the base for the Medical Corps, then variously warehouse photography studio, and since the 1990s to present, an office.

CONTEMPORARY CONSERVATION & RETROFIT

The tenant was reporting problems with leaks which we were asked to survey and make recommendations for remedial works. The leaks were largely arising from failing rainwater goods and overflowing parapets, exacerbated by more extreme rainfall. However, the 185m² of roof glazing in single Georgian wire patent glazing were also leaking and creating large amounts of condensation.

CONTEMPORARY CONSERVATION & RETROFIT

It was an impossible space to heat or cool and glare was a massive problem. It became clear that the roof and gable needed to be completely replaced. What started as a repair become a major opportunity for a deep retrofit once the tenant’s lease was up. The major challenge for the team was how to design, specify and install 185m² of new glazing that would meet all the regulatory and technical demands with a comfortable internal environment whilst preserving the character, without overloading the trusses.

CONTEMPORARY CONSERVATION & RETROFIT

Internally the ancillary spaces were moved to the basement and the original structure revealed and repaired with appropriate materials with modern interventions clear and contemporary in complementary finishes. The colour scheme echoes the military history with brass details.

CONTEMPORARY CONSERVATION & RETROFIT

The success of this project can be measured in the reduction of the Energy Performance Certificate from E to B and an increase in the rental value of 75%, justifying the investment by the landlord and attracting a new and very happy tenant.

CONTEMPORARY CONSERVATION & RETROFIT

The original architect is unknown but the building presents layers of historical significance in the architecture, technology and human activity that has taken place here. Therefore a conservation approach has been taken in developing concepts for how best to retrofit the fabric of the roof, interior and whole new servicing infrastructure, whilst preserving and enhancing its character. Several significant alterations were made to the building, particularly in the years of occupation by the Rifles. Not least after damage caused by a bomb dropped from a Zeppelin in 1915!

CONTEMPORARY CONSERVATION & RETROFIT

Super low-g glass with reduced transmittance but a clear appearance in pre-glazed aluminium units that preserved the sightlines were specified. The concrete tiles were replaced with manmade slates (natural slate was too heavy). Beneath, multifoil insulation was integrated over the historic sarking boards to reduce heat gain as well as insulate. All parapet gutters and flat roofs were insulated with warm roof liquid applied covering. Air tightness was improved at all junctions. This, with the removal of gas and installation of MVHR and ASHP, and full LED lighting, resulted in the EPC for the building being reduced from E to B, achieving PAS2038.