House Extensions Luton

An extension in Luton runs on two tracks: the planning route first, then building control. Luton Borough Council handles both, and it publishes exactly what it will inspect and what it will charge. We work alongside your designer on the planning side, coordinate the building control application, appoint the structural engineer and build to the calculations issued.

For Luton, 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 Luton: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

The eight inspections on a Luton extension

Luton Borough Council lists eight inspection stages for an extension to a house, shop or office, beginning with commencement and ending with completion of work. Stage 2 is inspection of the new excavation for foundations, so the trench is seen before any concrete goes in.

Stage 4 covers new walls, damp proof course and below ground drain pipes for falls and line. At the end, the council states that once the extension is approved and installer certificates are received, the completion certificate follows within five working days.

Housing in Luton

On the valuation list Luton counts about 85,500 homes, 28% flats and 72% houses; 13% predate 1919, 20% are interwar and 67% post-war. A rear extension on a terrace in Luton digs foundations close to both neighbours, so notices to both are normal, and 30% of homes here are terraced.

What building control charges

A single storey extension under 100 square metres carries a charge of £1,045 on a full plans combined payment, or £375 plus £700 if you split the payment. Those figures apply from 1 April 2026.

A two storey extension under 100 square metres is £1,245 on a full plans combined payment and £1,530 under a building notice. Full plans is the cheaper route in both cases, and it also gives you a checked design before the groundworks start.

The planning route, and the fast track

Luton offers a fast track householder application for £250, with a guaranteed decision within five working days of the end of the consultation period. It is not available if the property sits in a conservation area, and the request must be stated in the proposal description when the application is submitted. Only two of Luton's five conservation areas are primarily residential: Rothesay, designated on 7 July 2003, and Luton South, designated on 19 April 2010.

Six Article 4 directions are in force in Luton, and none of them removes permitted development rights for house extensions or alterations, so ordinary householder rights apply across the borough. Check which council you are dealing with before anything else, because an LU postcode does not mean Luton Borough Council. The LU1 outcode also takes in Caddington and Slip End, which are in Central Bedfordshire.

What is under the new foundation

Luton sits on Chalk bedrock, not London Clay, so the shrink and swell subsidence pattern that dominates north London is not the default assumption for foundations here. Above the chalk, the cover changes by area.

Clay with flints, described by the British Geological Survey as unsorted sediment with flint gravel in a sandy mud matrix, is mapped over the chalk at Stopsley, Round Green, Stockwood Park, Farley Hill and Wigmore. The Environment Agency's flood map for planning records Flood Zone 2 along the River Lea at Leagrave and through Wardown Park. Both change what the foundation and drainage design have to answer.

Kitchen extensions in Luton

53% of the houses in Luton 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 Luton; the build figures are in the table above.

Side return extensions in Luton

Side returns belong to Victorian and Edwardian terraces, and only 13% of homes in Luton 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 Luton

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 Luton often needs planning permission from Luton Borough Council. With 38% 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.

• Full fit-out, finishing and making good
• Steel goalpost frames where the rear wall opens up
• Bi-fold, sliding and French door openings to the garden

VOA Council Tax stock of properties, March 2025, for all 22 statistical areas in Luton. Counts rounded by the VOA.

For the wider picture around house extensions in Luton, see RSJ and steel beam installation in Luton, house extensions in Dunstable, side return infills, a garage conversion instead, house extensions across London and Crittall Doors Guide.

The GS Renovation Difference in Luton

An extension is where planning and building control have to be run in step, and Luton publishes enough detail to plan both properly. We work alongside your designer on the planning application, coordinate the building control application, appoint the structural engineer, build to the calculations issued and hold the programme against the council's eight inspection stages. The excavation stage and the drainage stage cannot be worked around, so the groundworks are booked with them in mind rather than in hope. Fully insured, with free no obligation quotations.

• Free follow-up visit after completion if anything needs attention
• Insulation and thermal detailing to current regulations
• 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.