A Starter Guide To Site Investigation or What You Need To Do To Avoid Problems With The Ground When Building.
“This quick guide is aimed at first time developers and home owners who wish to extend their homes, construct basements or subdivide their properties and self-build. Its purpose is to help them understand Site Investigation, what they need to do and how to go about obtaining quotes and a specialist report. It has been written in response to the many queries we have received in past 2 years particularly about London site investigations and from new site investigation clients in the Reading, Basingstoke, Swindon, Oxford, St Albans, Woking, Guildford, Watford, Bristol, Southampton areas where Geoinvestigate has recently opened a new site investigation hub office”.
It’s a fact – problems with the ground are one of the main causes of cost overruns, time delays and disputes in the construction and building industry whether your project is building a new house or constructing a major retail park.
Depending on where your development is located in the UK problems with the ground can range from abandoned mine workings, mine shafts, chalk and limestone sink and swallow holes, unstable slopes, shrinkable clays and trees, soft compressible river soils and peat, old quarries deep un-compacted weak fill, old foundations, expansive foundry slag and mine waste, land contamination and toxic and/or explosive mine or landfill gas.
Before building a developer, their principal advisor, planning consultant, consulting engineer or architect has a duty of care and a statutory requirement to investigate the land thoroughly to minimise risks to human health and the financial losses that might otherwise arise from contamination or building damage caused by poor ground.
Indeed in most cases you have no option but to investigate the ground. As part of planning procedure Local Authorities and their Planning, Building Control and Environmental Health Departments will require that they are provided at an early stage with a site investigation report. Normally in 2 parts this comprises an initial Phase 1 desk study (a relatively cheap, mostly office based exercise looking at historical maps, geological plans and environmental data lists), followed by a Phase 2 intrusive physical exploration of the site with say boreholes or test pits. Phase 3 is any special work needed at the end to make the site safe or stable such as removing contaminants or infilling mine workings.
It’s always advisable to get at least 3 price quotes from site investigation specialists or geotechnical or geo-environmental engineers as they are also known. Don’t necessarily restrict your quotes to local firms, as Northern companies working nationally across the UK and having lower overheads and labour costs can be much cheaper while still providing a very good, reliable service.
Don’t be surprised if after completion of the Phase 2 report there is need for some additional investigation and extra cost before planning permission is given. This is not untypical. The Authorities may have questions that need to be answered on a report they have read. In some instances this may lead to additional boreholes and testing and of course cost. Though some may argue that Authorities are creating extra work and don’t seem to care about spending other peoples money experience usually shows that more is to be gained by constructive dialogue and interaction with them than by taking a stubborn or non-cooperative stance.
As the site investigation specialist will expect to be paid for their extra work including answering queries or attending meetings it’s important that their quote has not been based on the expectation of overly favourable ground conditions and a minimal scope of work. Ultimately, you are going to pay extra for a cheap investigation that turns out to be inadequate and which still leaves questions to be answered – there is also the added risk of long delays before you can start building.
From our offices in the South, North East and North West of England, Geoinvestigate Limited provides a very good, reliable, cost effective, nationwide site investigation service. We provide expertise in the fields of site investigation, ground investigation, soil investigation, foundation investigation, Phase 1 and Phase 2 desk study and site investigation reports, geotechnical consultancy, environmental consultancy, geo-environmental consultancy, landfill gas monitoring, contaminated land assessment and remediation, building subsidence, slope stability, mineworkings, validation surveys as well as data acquisition using trial pits, boreholes and drilling. So whether it’s a site investigation in London, Bristol, Cambridge, Birmingham, Manchester, Lancaster or Carlisle you require please contact our Geotechnical and Geo-environmental engineers for a free no obligation quote or advice on obtaining a site investigation.