House Extensions Dunstable

An extension is a planning question, a building regulations question and a groundworks question, in that order. We handle the build and coordinate the professionals around it, including the structural engineer whose calculations the steel and the foundations are built to. We do not produce those calculations, and we are not architects or surveyors. This page sets out how the Dunstable side of it works.

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

Central Bedfordshire Council allows itself 8 weeks to decide a minor planning application

It allows 13 weeks for a major one. Inside that period, statutory consultation on a Central Bedfordshire application lasts 21 to 28 days. A householder extension is a minor application, so 8 weeks is the figure to plan around, and the clock starts once the application is valid rather than once it is sent.

Two documents shape what gets approved. The adopted development plan is the Central Bedfordshire Local Plan 2015 to 2035, recorded as taking effect on 22 July 2021. The council also adopted its Design Guide Supplementary Planning Document on 1 August 2023, and it applies to all new development in Central Bedfordshire. Your designer works to both, and we build what is approved.

Housing in Dunstable

The stock in Dunstable runs to roughly 17,660 dwellings, 28% of them flats and 72% houses, built 9% before 1919, 12% between 1919 and 1939 and 79% after 1945. A rear extension on a semi in Dunstable digs beside the attached neighbour, so one party wall notice is usual, and 33% of homes here are semi-detached.

Article 4 directions and the conservation area in Dunstable

The national planning data register lists seven Article 4 directions for Central Bedfordshire, and none of them is in Dunstable. That register is not always complete, so check the council's own Article 4 list for your address before relying on permitted development. A conservation area and your own title can also restrict what you build. Dunstable has one conservation area, reference CA43, one of 61 across Central Bedfordshire, and inside that boundary the position is different.

There is one more boundary worth checking on the west side. The Chilterns National Landscape boundary runs close to the south western edge of built up Dunstable, within about 65 metres of Whipsnade Road, but is roughly a kilometre from the town centre crossroads. Being near a designation is not the same as being inside it, and which side of the line you sit on is a matter of record.

The ground an extension bears on is not the same across the town

The bedrock beneath the Dunstable crossroads and the Priory Church is the Holywell Nodular Chalk Formation, on British Geological Survey 1:50,000 mapping. Around Whipsnade Road, Spoondell and Royce Close, in the west and south west, that mapping gives the New Pit Chalk Formation instead. Two formations means two answers on bearing, and the boundary between them does not follow the street pattern.

Superficial cover varies too. No superficial deposits are mapped over the crossroads or the Priory, while Head, described as sand, gravel, clay and silt, is mapped in the south of the town. Foundation depth is set by the engineer from a trial pit at the actual location. We dig it, record what it shows, and price the foundation from that.

Groundwater and flood constraints differ between parts of Dunstable

Dunstable town centre lies inside the Periwinkle Lane drinking water safeguard zone, which the Environment Agency classes as groundwater Source Protection Zone 2. The south eastern fringe of the town, near the Luton boundary, falls inside the Runley Wood safeguard zone, classed as Source Protection Zone 1, the innermost and most restricted. Along Luton Road that zone starts only past the edge of Dunstable.

River flooding is a separate question and a more comfortable one. The Environment Agency's Flood Map for Planning places the Watling Street and Icknield Way crossroads outside Flood Zone 2 and Flood Zone 3. Soakaways, drainage runs and excavation near a sewer still have to suit the zone you are actually in, and that is checked before the foundations are set out.

Kitchen extensions in Dunstable

61% of the houses in Dunstable are semi-detached or detached, which usually leaves room for a kitchen extension across the full rear width, with a steel beam over the opening into the house. The fit-out is priced on its own page, kitchen renovation in Dunstable; the build figures are in the table above.

Side return extensions in Dunstable

Side returns belong to Victorian and Edwardian terraces, and only 9% of homes in Dunstable 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 Dunstable

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 Dunstable often needs planning permission from Central Bedfordshire Council. With 44% of homes here semi-detached or detached, the side of the house is often an option too. Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• Bi-fold, sliding and French door openings to the garden
• Steel goalpost frames where the rear wall opens up
• Trial holes to set foundation depth near drains and trees

VOA Council Tax stock of properties, March 2025, for all 5 statistical areas in Dunstable. Counts rounded by the VOA.

Useful next reading for a house extensions project in Dunstable: RSJ and steel beam installation in Dunstable, house extensions in Luton, basement extensions, party walls and extensions, house extensions anywhere in London and Crittall Doors Guide.

Why Choose GS Renovation in Dunstable

An extension needs a designer, a structural engineer and a builder, and the gaps between the three are where extensions stall. We coordinate the engineer, make the building control application to Central Bedfordshire Council, and build the foundations, the structure and the fit out on one programme with one point of contact. The structural calculations come from the engineer we appoint, because we are a contractor rather than an engineering practice. GS Renovation Ltd is fully insured, registered in England, company number 14611254, and rated 4.9 from 31 reviews on MyBuilder. Quotations are free and without obligation.

• Insulation and thermal detailing to current regulations
• Clean, tidy and reliable tradespeople
• Drainage diverted or built over with the right approval in place

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.