27-29 Victoria Road, Farnborough, Hampshire

26th September 2017

Specialist Services

A second opinion from Ground & Water is able to rule out the requirement for gas protection measures, enabling a residential development to progress to completion.

Our Client

Our client was a modern, privately-owned property developer with a first-class reputation. The client is acknowledged as a leader in the Thames Valley and are one of the few names active in such a broad range of property sectors: regeneration, residential, commercial, mixed use, property investment and serviced apartments.


A mixed-use redevelopment providing two ground floor retail units with three floors of residential apartments above.


Our Challenge

We were approached for a second opinion on ground-gas risk by a medium sized developer in the Thames Valley. The initial risk assessment carried out by a competitor, suggested protection measures were required.

The Ground & Water Approach

The original desk study highlighted that there was a potential ground-gas (Methane and Carbon Dioxide) risk because of a historical, and local authority recorded, landfill site ~150m to the south-west of the development. This source being possible buried putrescible material within the landfill.

Having reviewed the original desk study and risk assessment, in October 2016, Ground and Water constructed three Terrier Windowless Sampler Boreholes to a depth of 4.45m bgl around the development. Combined groundwater and ground-gas monitoring wells were installed to 4.00m bgl in all trial holes. Ground and groundwater conditions were also evaluated and monitored. Ground-gas monitoring was carried out on six occasions between November – December 2016. A detailed risk assessment followed.


The Outcome

The results from the gas monitoring – relatively low Carbon Dioxide levels, no Methane and depleted Oxygen – and risk assessment revealed the site fell into a Characteristic Situation 1, where no precautions against the ingress of ground-gas were necessary.

No further action was considered necessary and the development could move ahead to completion.

Pin It on Pinterest