Contamination legacy resolved to make way for Bexley development

An ambitious scheme to redevelop a 1970’s high-rise blight in the London Borough of Bexley is now set to welcome its first new residents.  Erith Park, a £130m, 10 Ha mixed residential development replaces the former Larner Road estate of 8 tower blocks following extensive work which has transformed the area renowned for social disorder into a desirable location.

Clarkebond provided civil, structural and geo-environmental engineering services on the project which posed a number of challenges as a result of the original estate having been built on an abandoned clay quarry.  The quarry had been partially backfilled in the ‘70s with random fill containing a significant level of contamination which presented a potential risk to the underlying chalk aquifer.

Through close consultation with the Environment Agency and detailed quantitative risk assessment, Clarkebond was able to establish a series of protocols for adoption in the construction to enable development without the requirement for extensive site remediation.  A highly varied topography and a 13m difference in level across the site presented a particular challenge to the required high density development and to achieving compliance to the London Housing Design Guide Lifetime Homes and Code for Sustainable Homes Level 4.  Much of the new development was also required for disabled occupancy, and all site areas were required to allow for disabled access. The site being a bowl shape also presented particular drainage challenge to provide protection for all dwellings against flooding from a potential off-site overland flow exceedence event.  Reprofiling of the site involved moving 70,000m3 of earth. An earthworks balance was achieved utilising all granular demolition arisings and no contaminated soil was removed from site.

Clarkebond was able to address all constraints to achieve the objectives of the development and code compliance. The structural design and drainage were designed to provide fully effective protection of the underlying Chalk aquifer from potential contamination pathways. Apartment blocks extended to 7-storeys accommodating a variety of unit sizes and were designed to allow for conventional concrete frame construction with little or no recourse to transfer structures, providing a significant cost advantage assisting viability of the essentially public and affordable housing development.

The first phase of Erith Park, comprising 133 houses and 202 apartments will welcome its first new occupants this October.  The second phase of 22 houses and 222 apartments is due to be completed in 2017.

Client – Orbit Housing Association
D&B Contractor – Wates Living Space
Architect – Broadway Malyon
M&E Consultant – Design Brook
Consulting Engineers - Clarkebond