Project Description

Abbey Pynford’s Basement Engineering Specialist’s, recognised as a market leader in combining Geo-structural Solutions and Basement Construction, have exceeded client expectations to complete a very demanding year-long retro-fit project several weeks ahead of schedule.

The project adjacent to Marble Arch required the construction of a new basement with the volume of an Olympic sized swimming pool and depth of an Olympic diving pit. In order to achieve the client’s programme requirements; the priced scheme was proposed, designed and on-site within 4 weeks. The stability of the fragile, early Victorian, grade II listed property was paramount in importance and in order to enable the safe formation of such a large basement; a new hybrid underpinning solution combining several types of PynWall underpinning, Pynford stools, a 700mm thick lower ground floor slab and temporary piles with pyn columns were utilised. This negated the need for temporary works besides those that could be integrated to the permanent structure.

The 6m deep basement was excavated and finished to provide the client with a luxury living space. The complex project was only completed within the tight deadline through close co-operation between Abbey Pynford’s full time in house design team and the construction team during every phase of the project. Abbey Pynford’s innovative composite construction processes enabled the progression of superstructure works concurrent with the basement installation.

The Principal Contractor and client team for the project were very impressed with the speed and quality of the construction continue to work toward the client’s Olympic deadline.


Abbey Pynford completed the sub-basement structure in time, to budget and with Health & Safety at the heart of all their operations

Construction Phase Highlights


Using specialist restricted access piling equipment, Abbey Pynford installed over 70no. Temporary piles that are used to support the Ground Floor Transition Slab before permanent structural walls are completed within the basement.


With bespoke shoring and reinforcement designs, underpinning bases were installed around the entire perimeter of the property. The safety of our operatives is the number one priority whilst installing these bases.


The existing Grade II listed building was successfully supported on steel stools and a 700mm thick reinforced concrete transition slab was installed beneath the existing walls to transfer the building’s loads into the temporary piles.


Once the transition slab was completed, our Principal Contractor could begin works at Ground Floor level whilst we excavate beneath the slab and form a new luxury basement. Phasing the construction proved highly successful and ensured our programme was comfortably met.