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Flat roof extensions across Sunderland

If you live in Sunderland and want more space without moving, a flat roof extension is one of the most practical ways to get it. We handle the drawings, approvals and the build.

  • Guide price in SunderlandFrom £19,000 inc VAT
  • PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
  • Build time10–16 weeks on site
  • Postcode districtsSR1, SR2, SR4, SR5, SR6
Flat roof of an extension with a membrane finish, a roof lantern and flat rooflights

Do I need planning permission in Sunderland?

In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.

Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.

If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.

Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

Applications are decided by the local planning authority (your district, borough or unitary council).

Flat roof extension prices in Sunderland

Labour and material costs vary across the UK, so for Sunderland we use our North East England factor (×0.91). The ranges include VAT and exclude design, structural and council fees.

Typical rates in Sunderland: £1,590 to £3,050 per m² including VAT, depending on specification.

SizeEssentialStandardPremium
3 m × 4 m
12 m²
£19,000 – £22,500£22,000 – £28,500£28,000 – £37,000
4 m × 5 m
20 m²
£31,500 – £37,500£37,000 – £47,500£47,000 – £61,000
5 m × 6 m
30 m²
£47,500 – £56,000£55,500 – £71,000£70,500 – £91,500

For a figure based on your own dimensions, use our guide-price tool.

Who a flat roof extension suits

  • Homeowners who want maximum light from above
  • Modern and 1930s onwards houses
  • Extensions under first-floor windows where a pitch will not fit

Local to Sunderland

We cover Sunderland and the postcode districts SR1, SR2, SR4, SR5, SR6, SR9. Nearby, we also take on projects in Washington (5 miles), Houghton-le-Spring (6 miles), Jarrow (7 miles), South Shields (7 miles).

Seaham, in County Durham, is roughly 5 miles from Sunderland and also on our list. Across the North East, houses often have rear yards or modest gardens, so compact, well-lit single-storey extensions make the biggest difference.

What happens next

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    We visit your Sunderland home, measure up, talk through what you want and check the planning position.

  2. Design and approvals

    We draw the design, agree it with you and handle planning or permitted development checks and building regulations.

  3. Fixed written price

    With the design and specification agreed, you get a fixed written price and a start date.

  4. Build and sign-off

    The build is managed from start to finish, inspected at each stage and signed off on completion.

Common questions in Sunderland

How long does a flat roof extension take to build in Sunderland?

On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.

Do I need building regulations approval in Sunderland?

Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.

Do you cover all of Sunderland?

Yes. We cover Sunderland and the surrounding parts of Tyne and Wear. Site visits are free and there is no obligation.

Can I walk on a flat roof extension?

Only for maintenance unless it is designed as a terrace. A roof terrace or balcony needs planning permission and a different structure.

Are flat roof extensions cheaper?

Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,590 to £3,050 per m² including VAT.

Book a free site visit in Sunderland

We will measure up, check the planning position and give you honest guide figures.

  • Free, no-obligation site visit
  • Planning route checked before you spend on drawings
  • Written price once the design is agreed
  • Building control sign-off at the end

Prefer to talk? Call 0800 088 6341 or .

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