Project Description

Abbey Pynford Basement Engineering Specialists’ proven record of quality assured basement construction ensured the follow on appointment to construct an extension to the lower ground floor of a five-storey brick property in Belgravia, London.

Working closely with the project designers and in partnership with the principal contractor; Abbey Pynford Basement Engineering Specialists overcame the unique site restraints to ensure that the project was completed on time and within budget, despite encountering numerous unforeseeable obstructions.

Works consisted of the demolition of an existing vaulted cellar structure and the sequenced installation of a new R.C. basement extension. Abbey Pynford Basement Engineering Specialists innovative approach reduced the requirement for temporary works and minimised the possible time implications created by the very restricted access to the work area.


Abbey Pynford’s responses to queries were good and eloquent and the guys on site were helpful, proactive and forthcoming.

Construction Phase Highlights


In order to enable the lower ground floor extension, an existing vault structure was demolished. Safety was the key consideration as the thrust forces from adjacent vault structures required propping, as a careful sequence of demolition and construction was utilised.


Abbey Pynford Basement Engineering Specialists developed PynWall system was utilised beneath the garden walls on both flanks to retain the adjacent loads and support the existing structures without costly and inconvenient traditional temporary works.


Below slab drainage was installed within the new RC structure and included a 2m deep pump chamber & storage. Owing to the sequencing of works it was necessary to install the sump chamber following all underpinning, great care was required during excavation to prevent the undermining of the existing structure in very loose ground conditions.


The lower ground floor slab was cast in sections sequenced with the PynWall works, reducing the requirement for temporary works, minimising costs and the duration of the works.