Establishing your main service provider a

British Geological Survey:

The following website provides a map of bedrock and superficial deposits:

mapapps - geologyofbritain

Locate your building plot on the map, select surface geology (Bedrock & superficial) and refer to the geological key provided.

The superficial deposits are geologically recent and are classed as unconsolidated whereas the bedrock is the term used to describe the main mass of rocks forming the earth.

This map also shows any available borehole information (Select borehole scans) – the closer these are located to the building plot the better and will give more accurate information on the geology than the map alone (but it is still a desk top study – for information only).

If your plot has superficial deposits its more likely a more expensive foundation solution such as piling will be required and if you have impermeable soils such as clay or mudstone then more expensive surface water drainage solutions maybe required (as soakaways will be unsuitable).

It will be well worth your time contacting your local authority building control department armed with this information – they will likely have local knowledge of any developments in similar geological areas and be able to advise of any potential issues – remember you are trying to establish the likely substructure and surface water drainage solutions for your plot. The guidance document on how to produce a feasibility deals with some likely additional costs if this desk top study and subsequent discussions raise potential issues.

Another free online resource in connection with establishing the flood risk of your proposed site can be found at: flood-map-for-planning.gov.uk
Simply enter the postcode and the website will confirm the flood zone and likely impacts.

For example if it falls within flood zone 1 you don’t need to instruct a flood risk assessment (and its smaller than 1 hectare), any plots within flood zone 2 or higher you will be required to carry out a flood risk assessment. The guidance document on how to produce a feasibility deals with some likely additional costs if this desk top study raises some potential issues. Mark as complete once this desk top study has been completed.

Coal mining has occurred in more places within the UK than typically thought, the following website is a free online resource to identify if your proposed plot is located within a previous coal mining area:

mapapps2 - coalauthority

Enter the postcode of the site or locate via the interactive map and select all available search items. Our advice at this stage would be to seek some professional guidance if your search returns some previous mining results, the potential knock-on effects are likely to be showstoppers – ground remediation or very specialist foundation solutions rarely stack up financially for small residential schemes such as self-builds.

Another consideration that is surprisingly prevalent. This website provides locations and names of previous landfills:

www.qmul.ac.uk/geog/historiclandfill/maps/

Our advice at this stage is the same as the Coal Authority desk top study: seek some professional guidance if your search returns some previous landfill results, the potential knock-on effects are likely to be showstoppers – ground remediation or very specialist foundation solutions rarely stack up financially for small residential schemes such as self-builds. Mark as complete once this desk top study has been completed.

All buildings contain Radon gas! Radon is a colourless, odourless radioactive gas caused by the radioactive decay of naturally occurring uranium. It poses a potential danger to human health and can lead to lung cancer. If the recommended levels of Radon are exceeded.

The following website shows where high levels of Radon are found:

ukradon.org/information/ukmaps

If your proposed plot falls within a colour coded area it is likely additional radon protection will be required.

The guidance document on how to produce a feasibility deals with some likely additional costs if this desk top study raises some potential issues

A very useful free online resource is found at:

old-maps.co.uk

Enter your address and all the available maps displayed in the left hand tool bar (oldest at the top). It can be quite an interesting exercise viewing how the areas has changed over time at can provide some useful information on any previous land use for your plots and the adjacent areas. You are basically looking (hopefully without finding anything!) for any evidence aa previous industrial type land use as this could indicate contamination is likely.

If you can trace your plot back as a green field site from the 1800’s its as good as it gets!

You can view online for free to a certain scale or purchase a copy for around £15/map type.

The guidance document on how to produce a feasibility deals with some likely additional costs if this desk top study raises some potential issues.

If your own desk-top studies raise some environmental issues or you would like further information (prior to instructing a ground investigation report for example) a more specific paid environmental survey is available via:

https://www.envirocheck.co.uk/report/envirocheck-report

For a relatively small cost (Approx £250) the Envirocheck Professional report provides environmental data covering potential sources of contamination, previous industrial land use, flooding and sensitive land uses. All of the above and more enables you to accurately assess the potential risks that could affect a site.

Existing water and drainage searches are typically only available via your conveyancing solicitor who includes these searches as part of the due diligence process, but you may be in luck if the building plot is for sale with outline or full planning permission: the developer is more than likely to have had already commissioned these searches so request a copy of them.

Things to consider:

• Any existing services located within the building plot may require diversion or have an easement (no development within a certain distance)
• No foul or surface water services near the perimeter of the site will equate to additional time and expense in terms of installation and design. No surface water is less of an issue if the ground conditions are suitable for soakaways.
• Existing gas and electrical utility maps are easier to get your hands on; find out the mains supplier in the area and visit their website, the maps should be available for free (as it’s a health and safety issue should you accidentally ‘strike’ a service during excavation so they should be readily available) you may be required to create an account in order to gain access. Also the resultant search will only display any existing services within the specific building plot boundary – useful to know if there are any issues with diversions or easements but it will not confirm if services are available at the boundary (which you want in order to keep your new incoming mains costs low).

The website below is a free online resource providing maps showing a high level assessment of regional WWII bombing densities and will help in your decision on whether further more detailed research by a UXO specialist is required.

Particularly useful for developments in or around large cities.

The map indicates the potential for UXB to be present as a result of World War Two (WWII) bombing.

zeticauxo.com/downloads-and-resources/risk-maps

Our advice at this stage is the same as the Coal Authority desk top study: seek some professional guidance if your search shows anything above a low risk, the potential knock-on effects are likely to be expensive remediation strategies. Mark as complete once this desk top study has been completed.

In addition to carrying out the desktop studies you should always walk the course and check for the following:

• i) Any evidence of former site use – redundant buildings/foundations/hardstanding etc – this could lead to a whole host of problems including increased foundation costs and more chance of underground services being encountered.
• ii) Above or below ground mains services – this could lead to expensive service diversion costs.
• iii) The topography of the site – any significant slopes or changes in level and the difference in site levels versus the access point/neighbouring properties/boundaries – this could lead to expensive retaining walls, increased excavation/disposal of spoil and expensive foundations / drainage solutions.
• iv) Trees – size, type and location should be noted – if the trees have tree protection orders (TPO’s) this could result in root protection measures, additional protection to the foundations and deeper foundations in some cases, it could also dictate the site layout in extreme cases. you can find out either by checking if your local authority has a TPO map or if not by contacting your local tree protection officer, the possible implications are listed in the TPO section of the Guide on how to produce a feasibility section. Make a note of the tree type as this will also have an implication on the depth of your foundations.
• v) How is the site going to be accessed – any restrictions for deliveries/plant? – any weak bridges/narrow roads/sharp corners etc? – This could lead to additional delivery costs, smaller items of plant being required which reduces efficiency and in extreme cases will dictate the method of construction.
• vi) Any evidence of disturbed ground – specifically if you suspect any spoil has been disposed of on the site – this would suggest possible contamination.
• vii) Utilities/Services/Drainage: Should be picked up in your desk top studies but there’s no substitute for walking the course! Make a note of the type and location of all visible services including any manholes – lift them if you can and make a note of the depth.

All the potential issues above are considered in the feasibility cost template, simply identify the relevant issues.