GS Renovation builds house extensions in Leatherhead, from single storey rear additions to two storey work, building to the structural engineer's calculations. The ground varies across the town: the London Clay Formation is mapped under Kingston Road north of the station, and River Terrace Deposits of sand and gravel at the western end of Randalls Road. The foundation follows what is there. Fully insured, with free no obligation quotations.
The ground decides the foundation, and it changes across Leatherhead
The London Clay Formation is mapped as the bedrock under Kingston Road north of the station and the western end of Barnett Wood Lane, with Head deposits over parts of it. Highlands Avenue, in south east Leatherhead, is different: it is mapped on chalk with no superficial cover. Two extensions of the same size on those two streets can need different foundations.
Randalls Road splits as well. River Terrace Deposits of sand and gravel are mapped in patches at its western end and westwards towards the Fetcham boundary, while the eastern half has London Clay bedrock with no superficial cover. Head, where it appears, is described by the British Geological Survey as gravel, sand, silt and clay accumulated by downslope solifluction, soil creep and hill wash.
Flood risk in Leatherhead follows the River Mole
Environment Agency flood risk here is confined to a narrow corridor along the River Mole. It takes in Leatherhead Bridge and the western end of Bridge Street, the southern end of Waterway Road, and the Fetcham Grove and leisure centre land beside the river. The eastern end of Young Street is in Flood Zone 2 only.
The boundary runs tight to the water. Leatherhead Bridge and the western end of Bridge Street, on and beyond the river crossing, fall within Flood Zone 3. The town centre stretch of Bridge Street, east of about the Running Horse, lies outside both Flood Zone 2 and Flood Zone 3. Where your address falls changes what the application has to deal with.
Which plan your extension is judged against
The adopted development plan covering Leatherhead is the Mole Valley Local Plan 2020 to 2039, adopted on 15 October 2024. Leatherhead has no neighbourhood plan and no designated neighbourhood area, so that Local Plan is the only district development plan document that applies. Neighbouring Ashtead and Bookham are in a different position, having both had their neighbourhood plans made in May 2017.
We are a contractor, not a planning agent. What that means in practice is that we build what has been approved, and we say so when a proposal looks like one that needs an application before it needs a builder.
The inspections an extension triggers
The Southern Building Control Partnership lists an excavations inspection, to confirm foundations have been dug to a satisfactory depth. On ground that changes from chalk to London Clay to river terrace sand and gravel within one town, that is the stage which catches a foundation designed for the wrong material. We book it, and nothing is poured until it has happened.
The partnership is a shared service covering three council areas: Mole Valley, Reigate and Banstead, and Tandridge. Your application and your inspections go there rather than to Mole Valley District Council. We make the application and coordinate the visits, so there is one point of contact.
- Architectural drawings and structural engineer coordination
- Building control inspections at foundation, damp course and steel stages
- Single and double storey extensions
- First fix and second fix plumbing and electrics throughout
- Party Wall Act notices for excavation near a neighbour's wall
Trusted House Extensions in Leatherhead
An extension in Leatherhead is decided at the bottom before it is decided anywhere else. The ground changes from chalk to London Clay to river terrace sand and gravel inside the town, so the foundation is designed for the address rather than for the size of the room. We build to the structural engineer's calculations, book the excavations inspection before anything is poured, and coordinate the building control application throughout. We are fully insured and quotations are free and carry no obligation.
- Insulation and thermal detailing to current regulations
- Party Wall notices served for excavation near a neighbour's wall
- Fully insured, with cover in place on every site
- Waste cleared as we go, not left piled in the garden
- Permitted development checked before you pay for a planning application
- Photographs kept at each stage for your records