the East of England cost guide

Extension costs in the East of England (2026): prices by area

Updated October 2026Prices include VAT and fees

Quick answerA 20m² single storey rear extension in the East of England typically costs £57,000 to £68,000 including VAT. Hertfordshire and Cambridge price near the South East, while Norfolk, Suffolk and the Fens are cheaper, because labour costs fall the further you get from London.

Typical prices in the East of England

the East of England the East of England, East of Englandindex 1.08

Single storey rear extension20 m² (5m × 4m)£57,000 to £68,000£3,090/m²
Kitchen extension with bifolds24 m² (6m × 4m), mid spec£75,500 to £90,000£3,420/m²
Double storey rear extension40 m² over two floors£91,500 to £109,500£2,490/m²
Dormer loft conversion2 bedrooms + en-suite£51,000 to £62,500
Velux loft conversion2 rooms£36,500 to £44,500
Garage conversion15 m² single garage£21,000 to £25,000£1,520/m²

All prices include 20% VAT, professional fees and statutory planning fees. Kitchen extension includes a mid-range kitchen, bifolds and a roof lantern.

Price my exact project

Building in the East of England

The East of England runs from the Hertfordshire commuter towns to rural Norfolk, and building costs follow that line. St Albans, Watford and Harpenden price close to the home counties, Cambridge is pushed up by its housing shortage, and towns such as Peterborough, Norwich and Ipswich sit nearer the national middle. Housing ranges from 1930s semis and post-war estates to older flint and brick cottages, which need more care to match.

What moves the price in the East of England

Distance from London

Hertfordshire and south Essex are firmly in the London labour market, so day rates and overheads are high. In Norfolk, Suffolk and Cambridgeshire outside the city, the same work is usually quoted for less. Our area figures follow this gradient postcode by postcode.

Clay and shrinkable soils

Large parts of Essex, Hertfordshire and Cambridgeshire sit on clay, which moves with the seasons. Near trees, building control often wants deeper or specially designed foundations. A trial hole early on avoids a nasty surprise once digging starts.

Matching older materials

Rural parts of the region have flint, render and soft red brick that is hard to match with modern stock. Reclaimed bricks or flint work add cost, and conservation officers may expect a close match on older or listed properties.

Planning and building control in the East of England

Standard English rules apply. Many single storey rear extensions are permitted development within the 3m or 4m depth limits, and the prior approval route can allow more. Green belt around London and Cambridge, plus conservation areas in market towns and villages, often reduce these rights. Every extension needs Building Regulations approval. Check with your district council, and confirm whether your house is listed before planning any changes.

Prices across the East of England

A 20m² single storey rear extension and a two-bedroom dormer loft with an en-suite, priced for each example postcode. All figures include VAT and fees.

Postcode	Area	Single storey, 20m²	Dormer loft	Index
CB1	Cambridge	£60,000 to £71,500	£53,500 to £65,500	1.13
AL1	St Albans	£61,500 to £73,500	£55,000 to £67,000	1.17
NR1	Norwich	£53,000 to £63,500	£47,500 to £58,000	1.00

Cost index for every postcode area in the East of England

Our index against the West Midlands base of 1.00. Higher means dearer. Enter a full postcode in the checker for district-level detail where we have it.

Area	Main town	Index
AL	St Albans	1.17
CB	Cambridge	1.13
CM	Chelmsford	1.10
CO	Colchester	1.05
HP	Hemel Hempstead	1.13
IP	Ipswich	1.01
LU	Luton	1.05
NR	Norwich	1.00
PE	Peterborough	0.99
SG	Stevenage	1.09
SS	Southend-on-Sea	1.07
WD	Watford	1.15

the East of England: common questions

How much does an extension cost in the East of England?

A 20m² single storey rear extension typically costs £57,000 to £68,000 including VAT, or about £3,090 per square metre. Expect the top of the range in St Albans, Watford and Cambridge, and lower figures in Norfolk, Suffolk and Peterborough.

How much does a garage conversion cost in the East of England?

Converting a single 15m² garage into a room typically costs £21,000 to £25,000 including VAT. Most garage conversions don't need planning permission, but some newer estates have conditions removing that right, so check your property's planning history.

Do I need special foundations on clay soil?

Often, yes. On shrinkable clay near trees, building control may ask for deeper trench fill or piled foundations. Your structural engineer will advise once the soil and nearby trees are known, and this is worth checking before you fix a budget.

Is a loft conversion cheaper than an extension here?

Usually. A two-room Velux loft conversion typically costs £36,500 to £44,500 including VAT, while a dormer with two bedrooms and an en-suite is around £51,000 to £62,500. Both add space without using garden.