House Extensions Cheshunt

GS Renovation builds rear, side and wraparound extensions in Cheshunt, across EN7 and EN8. Foundation design here depends on which part of town you are in, so a structural engineer is appointed before anything is dug. We coordinate the building control application and the inspections, and quotations are free with no obligation.

For Cheshunt, on London-derived ranges a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m²; Hertfordshire work generally runs below that. GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Cheshunt: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Why foundation depth changes across Cheshunt

The town sits on a west to east sequence of deposits, and foundation design follows it. BGS records bare London Clay in the west, then Taplow Gravel, then a belt of Enfield Silt, then Kempton Park Gravel through the town centre, then Alluvium on the valley floor. The bedrock under every part of Cheshunt tested on the BGS 1:50,000 map is the London Clay Formation, from Goffs Oak in the west to the Lee Navigation in the east.

The clay is why depth is never a guess. BGS names the London Clay as very susceptible to volume change, the shrink and swell behaviour that causes subsidence and heave. At the Church of St James in Goffs Oak, BGS maps no superficial deposit at all, so London Clay lies directly under the topsoil. On ground like that, the footing is designed for the clay itself.

Housing in Cheshunt

Cheshunt has around 18,660 homes on the Council Tax list: 84% post-war, 9% interwar and 6% predate 1919, with 25% flats and 75% houses. A rear extension on a terrace in Cheshunt digs foundations close to both neighbours, so notices to both are normal, and 41% of homes here are terraced.

Gravel and alluvium under town centre footings

Through the town centre the footings start in gravel. BGS maps the Kempton Park Gravel Member as the surface deposit under Cheshunt town centre, covering the whole of Turners Hill and Crossbrook Street and the western part of Windmill Lane. The eastern end of Windmill Lane runs onto Alluvium instead. BGS gives that gravel an average thickness of 6 metres, thicker again where it fills deep hollows, and describes it as sand and gravel, locally with lenses of silt, clay or peat.

East of the town the ground changes again. BGS maps Alluvium on the Lea valley floor at Cheshunt, from the ground around Cheshunt railway station eastwards to the Lee Navigation, and describes it as clay, silt, sand and gravel. A lens of silt, clay or peat under one corner of a footing is what makes a trial hole worth digging before a price is fixed.

Flood zones, Green Belt and protected ground

Flood risk in Cheshunt is an address by address question. Environment Agency Flood Zone 3 covers the Lea valley floor on the eastern edge of Cheshunt, along the Lee Navigation and the Cheshunt marsh land. The Churchgate area sits outside any mapped flood zone. A narrow Flood Zone 2 fluvial corridor runs through the town centre at Turners Hill, so the position there is checked property by property.

Designations bite on the edges of the town. Land at Cheshunt Park and Theobalds Park is Green Belt, which restricts the scale of extension permitted on properties within it. Turnford and Cheshunt Pits is a Site of Special Scientific Interest on the eastern side of the town, reference 2000066. Half Moat Manor House moated site and its associated leat is a scheduled monument, list entry number 1012163.

Permitted development and the Broxbourne planning route

Outside a conservation area, permitted development rights in Cheshunt apply in the usual way. No Article 4 direction for Broxbourne is recorded on the national planning data register, but that register is incomplete, so we check the council's own Article 4 list for the address. Churchgate is the only one of the six Broxbourne conservation areas that falls inside the Cheshunt built-up area, and it covers about 15 hectares, under 2 per cent of the roughly 800 hectares of the built-up area.

Where a question needs settling before drawings are paid for, there is a free route. Broxbourne runs a duty planner service for householders, offering ten minute telephone appointments on Wednesdays between 9am and 1pm, bookable up to two weeks ahead. Work to any tree inside a Broxbourne conservation area needs an application to the council, which matters where a new foundation sits close to one.

Kitchen extensions in Cheshunt

55% of the houses in Cheshunt are terraced. On a terrace the kitchen extension is built out from the back, into the side return where the house has one or across the full rear width, and a steel beam takes the old back wall so the kitchen and the new room become one space. The fit-out is priced on its own page, kitchen renovation in Cheshunt; the build figures are in the table above.

Side return extensions in Cheshunt

Side returns belong to Victorian and Edwardian terraces, and only 6% of homes in Cheshunt predate 1919, so they are the exception here; most extensions run across the full rear width instead. Our side return extension page covers the build in detail, with build rates of £2,400 to £3,200 per m².

Double storey extensions in Cheshunt

Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Cheshunt often needs planning permission from Broxbourne Borough Council. On the 41% of homes that are terraced, the neighbours' windows usually decide the depth. Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• Trial holes to set foundation depth near drains and trees
• Scaffolding, site set-up and safe access on tight terraced plots
• Planning applications and permitted development assessments

VOA Council Tax stock of properties, March 2025, for all 6 statistical areas in Cheshunt. Counts rounded by the VOA.

Alongside house extensions in Cheshunt, the pages that usually help next are RSJ and steel beam installation in Cheshunt, house extensions in Oakwood, double storey extensions, the Party Wall Act process for extensions, house extensions anywhere in London and Bifold vs Sliding Doors.

Why Choose GS Renovation in Cheshunt

Extensions in Cheshunt are priced on the ground, not on a rate per square metre. We appoint the structural engineer, dig trial holes where the mapped deposits warrant it, and build the foundation the engineer designs for what is actually under your garden. Planning, building regulations and the party wall position are then run as one sequence by one point of contact. Fully insured, registered in England, company number 14611254.

• Brick and mortar matched to the existing elevation
• Free follow-up visit after completion if anything needs attention
• Insulation and thermal detailing to current regulations

Reviewed jobs near Cheshunt

3 MyBuilder reviews from Waltham Cross, with each customer's own job title:

• Kitchen Restoration, Waltham Cross, 7 Jan 2023 (5 out of 5)
• Kitchen refurbishment, Waltham Cross, 3 Sep 2021 (5 out of 5)
• Medium sized bathroom refurb, Waltham Cross, 9 Oct 2017 (5 out of 5)

Read all 31 on our reviews page.

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.