A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
Cost is usually the first question about a double-storey extension, so here is the guide for the East of England: £63,000–£126,000 including VAT. We cover the whole of Norfolk, with Norwich, Great Yarmouth, King's Lynn and Thetford among the main centres. Because each UK nation sets its own rules, we check the requirements in England for your property, then put a firm price on paper following a free survey.
- Guide price
- £63,000–£126,000 inc VAT
- Time on site
- 14–22 weeks on site
- Planning rules
- England
- Price level
- About 5% above the national guide
- Towns listed
- 6
- Survey
- Free, with a written quote
How much does a double-storey extension cost in Norfolk?
In Norfolk, guide figures for a double-storey extension sit at £63,000–£126,000, VAT included. We set them using rates for the East of England, currently about 5% above the national guide. The table shows what pushes a project towards either end of the range; your own price is set after a free survey.
| Type of job | What it usually involves | Guide in Norfolk |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £42,000–£68,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £63,000–£126,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £105,000–£189,000 |
The main things that change the figure:
- How the new roof joins the existing roof
- Bathrooms, en-suites and plumbing on the upper floor
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What’s included?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Roof structure tied into the existing roof, tiled to match
- Electrics, plumbing and heating by qualified trades, with certificates
- Building control inspections and completion certificate
Homes in Norfolk
Flint is everywhere in Norfolk, often combined with brick quoins and red or black-glazed pantile roofs. Norwich has Victorian terraces and interwar suburbs around its medieval centre, Norfolk reed thatch survives across the county, carrstone is used in the west, and coastal towns such as Great Yarmouth and Cromer have Victorian terraces and newer bungalows.
Flint walls often need lime repointing and careful repairs, and pantile roofs need matching tiles. Norwich terraces suit loft conversions and rear extensions, while coastal bungalows commonly take loft rooms, porches and new windows.
Norfolk is dry but exposed, with strong easterly winds, an eroding coast in places and low-lying land around the Broads.
Planning and building rules in Norfolk
Planning law differs across the UK. For a home in Norfolk, it is the England rules below that count, and we check them with the council ahead of any quote.
In England, a two-storey rear extension can only be permitted development if it is no more than 3 m deep, at least 7 m from the rear boundary and finished to match the house. Most double-storey and all two-storey side extensions need full planning permission.
Building Regulations approval is needed, with structural calculations for beams, foundations and the roof. The Party Wall etc. Act 1996 often applies on semi-detached and terraced houses.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
We look at the job
A free survey comes first. It gives us what we need to price a double-storey extension properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Price and scope agreed
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Plan and prepare
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Build and hand over
Work goes ahead as scheduled and you deal with one contact throughout. When the last trade leaves, we clear and clean the site, talk you through what has been done and pass on any certificates and care instructions.
What you can expect from us
Questions about a double-storey extension in Norfolk
Can we live at home while it is built?
Most families stay at home during a double-storey extension. The new structure is built outside first, and we only break through into the existing rooms near the end, usually one floor at a time. Upstairs, this may mean a bedroom is out of use for a week or two. We fit dust screens, protect floors and stairs, and plan any time without water or power in advance.
How is the new roof joined to the existing house?
The new roof is usually tied into the existing roof so the two read as one. On a rear extension this often means a lower ridge or a hipped end, with valleys where the slopes meet. We strip back some existing tiles, fix new rafters and battens, and lay matching tiles or slates. Lead or proprietary flashings seal the junctions so water runs off properly.
How much will a double-storey extension cost in Norfolk?
As a guide, expect to pay £63,000–£126,000 including VAT for a double-storey extension in Norfolk. That range is adjusted for the East of England, which runs about 5% above the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
How much does a double-storey extension cost?
A typical double-storey extension of 30–40m² across both floors costs £63,000–£126,000, built to a plastered finish. As a rough guide, allow around £1,400–£2,600 per square metre plus fixed costs for groundworks, scaffolding and fees. The second storey usually costs less per square metre than the first, because foundations and roof are shared. Bathrooms upstairs and a complex roof add most. We confirm a fixed price after the survey.
Towns in Norfolk
Below is our list of Norfolk towns for a double-storey extension. If yours isn't shown, we may still cover it, so it is worth asking us directly.