Groundwork

Specialist groundworks contractor for London and the South East

O'Sullivan Civil Engineering delivers specialist groundworks for residential, commercial and heritage projects across London and the South East. With over 40 years in the construction industry, our teams bring practical, site tested experience to every substructure contract - from straightforward foundation works to complex multi phase schemes in constrained urban environments.

We work as a trusted subcontractor to civil and structural engineers, main contractors and developers who need reliable, quality focused delivery on below ground works.

Groundworks services

We provide a comprehensive range of groundworks and substructure solutions, including:

  • Traditional and engineered foundations
    strip, pad, raft and trench fill foundations for new build and refurbishment​
  • Underpinning
    mass concrete, beam and base, and pile and beam underpinning to existing structures
  • Drainage and utilities
    foul and surface water drainage, pump chambers, soakaways and utility diversions​
  • Excavation and bulk earthworks
    cut and fill, muck away and formation preparation
  • Tunnelling and specialist substructure works
    including access tunnels and culverts in sensitive environments​
  • Void formers and reinforcement installation
    underground pump chambers and service ducts
  • Concrete works
    ground beams, pile caps, slabs and retaining walls​

Groundworks for complex and sensitive sites

Many of our groundworks projects sit within live urban environments, on tight plots, or beneath or adjacent to occupied buildings and sensitive heritage structures. Our teams are experienced in assessing site‑specific risks – including unstable ground, high water tables and proximity to neighbouring foundations – and working closely with engineers to plan and sequence works accordingly.​

We have delivered groundworks across inner‑city London, heritage buildings, high‑end residential neighbourhoods and commercial developments in Surrey, Kent, Berkshire and beyond.​

Working with engineers and main contractors

Civil and structural engineers rely on us to translate groundworks designs into safe, efficient construction on site. We engage early in the design process to review buildability, programme and temporary works requirements – helping de risk the project before breaking ground.

  • Early contractor involvement for sequence and methodology review
  • Coordination of temporary works design and installation
  • Clear progress reporting and change control throughout
  • Direct liaison with local authorities, utility providers and neighbours where required

Project experience

Our groundworks portfolio spans London and the wider South East, with completed projects including Egerton Crescent, Eaton Place, Holland Villas Road, Montpelier Street, Montana Road (Wimbledon), Parkside, and Bevis Marks Synagogue in the City of London.

We also have significant experience delivering groundworks for prestigious homes and commercial buildings across Surrey, including Reigate, Esher, Tadworth and Beaconsfield.