Household Cavalry Museum

Interior images (finished work) courtesy of Paul Carter; exterior images courtesy of James Brittain

Designed by architect William Kent, and built after his death in 1748, The Horse Guards building is the headquarters of The Household Cavalry. The project involved the creation of a modern museum telling the history of the Household Cavalry and allowing public access for the first time.

In the north pavilion gallery, the ground floor has a groined brick vaulted ceiling with a floor to ceiling height of 5m. The vaults and internal walls and chimneys above are supported off a grid of six cruciform stone columns and external walls. Above the vaulted ceiling is a suspended timber first floor.

This pavilion had suffered 150 - 250mm differential settlement in the south-east corner while its north wall also bulged 60mm outwards at first floor level.

In the 1920s the north-west corner and west wall were underpinned and a concrete filler joist slab inserted, creating a mezzanine floor slab that successfully retained the vaults from spreading.

Notable Features

During the design stage opportunities for investigation and opening up of the suspended timber floor were frustratingly limited.

A scheme was designed to allow flexibility during implementation on site. Sloping steel flats restraining points of the vaults were tied back to a strengthening system consisting of two horizontal trusses in the plane of the floor that provided a stiff diaphragm. These trusses comprised steel channels for the cords, fixed to the wall, and steel flats for diagonal struts.

Early in the project the floor boards were lifted to reveal a largely intact original Kent floor with some insensitive modern replacements. The timber joints were of particular interest so, in close consultation with English Heritage, each one of these was surveyed and details recorded.

Once the strengthening work was installed, the concrete floor was carefully sawn out in sections. The actual movement in the existing building was difficult to predict, so an extensive detailed monitoring regime was established before work started. No movement was observed during or after completion.

In November 2008 the excellence of Gifford’s conservation work was acknowledged with a commendation in the Heritage Award for Buildings category at the Institution of Structural Engineers Annual Awards.