House Extensions Royston

An extension is a planning question, a structural question and a drainage question at the same time. We build it, coordinate the structural engineer, and arrange the building control applications and inspections. We can work alongside your architect or planning consultant, and we do not draw the scheme or write the calculations ourselves. This page sets out what governs an extension in Royston and what the ground under it is.

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

North Hertfordshire District Council decides your extension, against a plan adopted in November 2022

The local planning authority for Royston is North Hertfordshire District Council, and the development plan is the North Hertfordshire Local Plan 2011 to 2031, adopted on 8 November 2022. That plan is the document your application is judged against.

The council also adopted the North Herts Design Code as a supplementary planning document on 29 June 2026, supporting Local Plan policies SP9 and D1. A design drawn up before that date is worth checking against it before it is submitted. We build to the drawings and the conditions as approved, and we raise anything on site that would depart from them.

Housing in Royston

Roughly 8,040 dwellings sit on the valuation list for Royston. 80% are houses and 20% flats, and by age 10% predate 1919, 4% are interwar and 86% post-war. A rear extension on a terrace in Royston digs foundations close to both neighbours, so notices to both are normal, and 26% of homes here are terraced.

Royston has no Article 4 direction, so householder permitted development rights are intact

There is no Article 4 direction anywhere in Royston. North Hertfordshire has only two, both made on 9 October 2012, covering Hitchin Conservation Area and Stockens Green Conservation Area.

The rights those directions remove elsewhere, enlargement or alteration of a house, roof alterations, porches, hard surfaces, chimneys and flues, gates, walls and fences fronting a highway, and exterior painting, are not removed anywhere in Royston. Permitted development still has its own size and position limits, and a listed building or a conservation area address changes what is available. We check the status of the property before the design is fixed. Most Royston houses were built after 1945, and on those plots the usual choices are a single storey rear or kitchen extension, a wrap-around, a double storey extension or a porch. Under permitted development a single storey rear extension can project 3 metres on a semi or terrace and 4 metres on a detached house, up to 4 metres high, with larger depths possible through prior approval. A wrap-around, which goes beyond both the rear and a side wall, usually needs planning permission. A double storey rear extension is limited to 3 metres deep and must stay 7 metres from the rear boundary, so most double storey schemes need an application. A porch under 3 square metres and 3 metres high, set at least 2 metres from a highway boundary, needs none. The price guide on this page gives indicative square metre ranges for rear, wrap-around and double storey work.

Two things to settle before the drawings: your neighbours' light and any protected tree

Local Plan Policy D3, Protecting living conditions, is the policy an objection from a neighbour will be tested against, and it names loss of daylight and sunlight, overlooking and dominance among the harms the council will consider. Designing against those three at the start costs less than answering them once an application is in.

On trees, the 2007 conservation area plan for Royston does not show every tree protected by a Tree Preservation Order and does not constitute a tree survey. Protection has to be checked with the council rather than read off the map. A protected tree near the foundation line affects the consent and the foundation design together.

What your foundations meet depends on which part of Royston you are in

The bedrock is not the same across the town. Royston sits about 200 feet above sea level in a shallow bowl in the East Anglian Heights chalk escarpment, a continuation of the Chilterns. British Geological Survey mapping puts New Pit Chalk Formation under the higher ground south towards Therfield Heath and Sun Hill, and under the built up area south of the town centre. The older Holywell Nodular Chalk is confined to the northern part of the town.

The superficial cover changes as well. The same mapping shows dry valley deposits of clay, silt, sand and gravel on the ground south west of Royston towards Therfield Heath, and glacial till of the Lowestoft Formation on the higher ground due south. Foundation depth follows the trial hole rather than the map, and we dig before the engineer fixes the design.

Kitchen extensions in Royston

62% of the houses in Royston 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 Royston; the build figures are in the table above.

Side return extensions in Royston

Side returns belong to Victorian and Edwardian terraces, and only 10% of homes in Royston 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 Royston

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 Royston often needs planning permission from North Hertfordshire District Council. With 50% 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.

• Planning applications and permitted development assessments
• Flat and pitched roofs with rooflights or lanterns
• Roof works and structural alterations at roof level

VOA Council Tax stock of properties, March 2025, for Royston North & Central and Royston South, West & East. Counts rounded by the VOA.

Related reading for Royston homeowners planning house extensions: RSJ and steel beam installation in Royston, house extensions in Letchworth Garden City, double storey extensions, garage conversions in London, house extensions anywhere in London and Bifold vs Sliding Doors.

Trusted House Extensions in Royston

An extension has two approval routes running in parallel, and confusing them is what causes delay. Planning permission, or a lawful development certificate, is decided by North Hertfordshire District Council. Building regulations approval and inspection are separate from it. We build the scheme, appoint and coordinate the structural engineer, arrange the building control applications and inspections, and keep the foundation design tied to what the trial holes actually show. You deal with one point of contact for the groundworks, the structure, the roof, the services and the finishes. GS Renovation Ltd is fully insured, registered in England, company number 14611254, and rated 4.9 from 31 reviews on MyBuilder.

• Weathertight shell reached before the fit-out begins
• Neighbours given notice before the noisy stages
• Building control inspected at foundation, damp course and steel stages

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.