Many homeowners and developers looking to increase property value and maximise floor space with a basement excavation, especially in areas where land is limited, will need planning permission from a local authority. Whether you are planning a basement beneath an existing structure, or as part of a new build, a basement impact assessment is essential.
Basement developments can introduce a number of complex risks. Your basement development’s impact will need to consider the effects of the following:
- Disruptions to groundwater levels and flow.
- Increased surface water or sewerage flooding.
- Ground movement which can damage neighbouring properties or infrastructure.
- Potential slope stability risks.
This assessment should be specific to the site, and its proposed development. If not properly assessed and managed effectively, these risks can lead to significant planning delays, additional construction costs, or even legal disputes from adjoining properties.
At Earth Environmental & Geotechnical, we provide detailed Basement Impact Assessments (BIA) to meet planning authority requirements, helping to identify these risks early on before development begins. Our expert team provides expert insight into whether a basement development is viable, what mitigation strategies may potentially be needed, and how your development will need to gain compliance with local planning policies, Building Regulations, Environmental Health standards, and Utility Provider requirements.
Our Basement Impact Assessments are designed to support planning applications and address council concerns, mitigate potential impact on neighbouring properties and infrastructure, and ensure compliance with policies such as Camden’s CPG4.
Do You Need a Basement Impact Assessment?
Whilst several London boroughs have published detailed guidance on basement assessments, such as Kensington, Fulham, Westminster, Haringey, Chelsea and Camden, many other Local Authorities do not have specific guidance on how to complete your Basement Impact Assessment.
Having expert knowledge and a rigorous process in place is essential to ensure your basement development will have no negative impact, meet planning requirements, and minimise environmental risk.
At Earth Environmental & Geotechnical, we understand these requirements and consistently deliver high-quality Basement Impact Assessments (BIA) to help secure approval.
Basement Assessment Services We Provide
We offer more than just compliance. Our experienced team of highly skilled and fully qualified engineers includes:
- Chartered geologists with hydrogeology expertise.
- Chartered civil engineers with ground engineering experience.
- Chartered engineering geologists.
- Surface water and drainage specialists.
We have successfully delivered BIAs for a wide range of clients from individual homeowners to architects, structural engineers, and specialist basement contractors to provide robust Basement Impact Assessments. Our team has supported developments across the UK, particularly our Reading Team who have worked on several prestigious locations, throughout London and surrounding areas.
What is involved in a Basement Impact Assessment or BIA?
Our Basement Impact Assessments follow a structured, rigorous process designed to meet local authority expectations and minimise risk to neighbouring structures and the surrounding environment.
- Desk Study
Firstly, a Desk study is completed to determine the scope of the ground investigation required, including the geology, hydrology, previous land use, and surrounding infrastructure of the site.
- Site Investigation
Secondly, the initial desk study is followed by a site investigation. The outcomes of the site investigation will be collated in a site investigation report. A ground movement analysis and a building damage assessment may also be required. This is to ensure that ground movements will not have a detrimental effect on surrounding structures, including buildings and buried infrastructure. Retaining wall analysis may also be required.
- Impact Analysis
Thirdly: we then work closely with the structural engineer and the architect to model and assess predicted movement, amending designs to bring movement into acceptable limits. We use industry-leading software like Pdisp, Xdisp, SlopeW and ModFlow to assess ground movement, slope stability, groundwater flow, and potential structural impact.
Speak to Our Experts Today
If you are planning a basement conversion, extension, or new build with subterranean levels, do not leave it to chance. Contact Earth Environmental & Geotechnical today for a robust, professional Basement Impact Assessment tailored to your site.
Call us or use the contact form below to get expert advice.
