Geology Maps UK
Explore British Geological Survey bedrock, superficial deposits and ground hazard mapping for any UK location — the essential baseline for understanding foundation conditions.
Updated: periodically as BGS republishes mapping · Last checked by Maplify: August 2026
What This Layer Shows
This layer maps British Geological Survey bedrock and superficial deposit geology at 1:50,000 scale, alongside GeoSure hazard ratings for shrink-swell clay, landslide susceptibility, compressible ground, collapsible deposits, running sand and soluble rock dissolution, plus radon potential and groundwater vulnerability classifications.
Together these provide the geological baseline that informs foundation design, drainage strategy and site investigation scoping before any intrusive ground investigation is commissioned.
Why It Matters
Understanding the underlying geology shapes almost every technical decision on a development site — from foundation type and depth to drainage design and the presence of naturally occurring hazards like radon. Engineers and developers check this layer at the earliest stage to scope a targeted, cost-effective site investigation rather than a generic one.
Because geological mapping is generalised at the published scale, this layer is best used to inform the brief for a site-specific investigation rather than as a final answer on ground conditions.
How to Interpret the Map
Bedrock Geology
Solid rock formation underlying the site, at 1:50,000 scale.
Superficial Deposits
Quaternary materials sitting above bedrock — glacial till, alluvium, river terrace gravels.
GeoSure Hazard Ratings
Shrink-swell, landslide, compressible ground, collapsible ground, running sand and dissolution classifications.
Planning and Development Implications
Geological conditions inform structural engineering decisions on foundation type and depth, which in turn affect scheme cost and programme. Higher hazard ratings for shrink-swell clay or landslide susceptibility can require deeper or specialist foundations, while elevated radon potential triggers Building Regulations protection requirements for new dwellings.
None of these factors typically prevent development outright, but they should be identified and costed at feasibility stage rather than discovered during detailed design.
What to Do When a Site Is Affected
- 1
Review bedrock and superficial geology mapping alongside the relevant GeoSure hazard ratings for the site.
- 2
Share findings with a structural engineer to inform foundation design assumptions.
- 3
Commission a site-specific ground investigation targeted at the flagged hazards.
- 4
Factor radon protection measures into the design if elevated radon potential is shown.
- 5
Check the wider Geology & Ground Risk layer for coal mining and contamination context.
This is general guidance, not professional or legal advice — confirm specifics with the relevant authority or a qualified professional.
Official Data Source
Data Freshness
Important Limitations
- Geological mapping is generalised at the scale published — localised variation can exist within a single mapped unit.
- This map does not replace a site-specific ground investigation with boreholes or trial pits.
- Hazard ratings indicate susceptibility, not certainty — always confirm ground conditions before design.
Common Use Cases
Structural Engineers
Establish foundation design assumptions from bedrock and hazard data.
Property Developers
Scope site investigation budgets before committing to acquisition.
Self-Builders
Understand baseline ground conditions before commissioning design work.
Surveyors
Factor geological hazard ratings into valuation reports.
Related Layers
Geology checks are often run alongside these related searches.
Related Guides
Frequently Asked Questions
What is bedrock geology?
Bedrock geology is the solid rock formation underlying an area, mapped by the British Geological Survey at 1:50,000 scale, providing the baseline for rock strength, groundwater flow and foundation bearing capacity.
What are superficial deposits?
Superficial deposits are the Quaternary materials — glacial till, alluvium, river terrace gravels — sitting above bedrock, strongly influencing drainage design and foundation options.
What does the shrink-swell clay layer show?
It shows BGS GeoSure hazard ratings for clay soils that expand when wet and shrink when dry, a common cause of UK subsidence.
Is radon risk part of the geology map?
Yes, radon potential is included, relevant to whether Building Regulations radon protection measures are required for new construction.
How is this different from the Geology & Ground Risk page?
This page focuses on the underlying geological mapping; the Geology & Ground Risk page adds coal mining and contamination-specific risk layers for a fuller site picture.
Explore Geology Data on Maplify
Search any UK location to see bedrock, superficial deposits and ground hazard mapping.
Dataset Details
| Provider | British Geological Survey |
| Geometry type | Polygon |
| Coverage | Great Britain |
| Update schedule | Periodic, as BGS republishes mapping |
| Reference date | August 2026 |
| Licence | Open Government Licence v3.0 |
References and Methodology
Reviewed by the Maplify data & editorial team
Maplify displays official-source data for desktop screening and due diligence. We document where each dataset comes from, how it is processed, when it is checked and where its limitations matter.