Cost Guide · Updated June 2026 · UK Roofing

How Much Does a Pitched Roof Conversion Cost in 2026?

Converting a tired, leak-prone flat roof to a pitched (tiled) roof is one of the best-value roofing upgrades in 2026 — it cures persistent leaks, lasts decades longer, and lifts kerb appeal. Expect roughly GBP 5,000 to GBP 9,000 over a garage or porch and GBP 9,000 to GBP 15,000 over a single-storey extension, or about GBP 200 to GBP 360 per square metre. This 2026 guide breaks down the cost ladder by span, what drives the price, and a worked GBP 11,400 example.

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GBP 200-360 per m²
Updated June 2026
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Cost Ladder · 2026

Pitched Roof Conversion Cost by Size

Prices include stripping the existing flat roof, fixing new wall plates, erecting the pitched structure, felt, battens, concrete interlocking tiles, fascias, soffits, guttering and scaffolding.

StructureApprox areaTypical 2026 cost
Porch / bay roof5-10 m²GBP 3,500-6,000
Single garage15-20 m²GBP 5,000-9,000
Single-storey extension20-35 m²GBP 9,000-15,000
Double garage / large rear35-50 m²GBP 14,000-20,000

London and the South East run roughly 10 to 20 percent higher. Clay tiles or natural slate add 15 to 40 percent over concrete interlocking tiles.

Price Drivers

What Drives the Cost

  • Span and structure: prefabricated trusses are cheaper than a hand-cut roof; wide spans and valleys add labour and timber.
  • Tile choice: concrete interlocking tiles are the budget option; clay and natural slate cost significantly more.
  • Wall plates and joists: if a structural engineer confirms the existing flat-roof joists and wall plates are sound, reusing them saves money.
  • Scaffolding and access: two-storey or restricted-access sites cost more to scaffold.
  • Insulation: a warm-roof build-up with insulation between and over rafters adds cost but improves comfort and Part L compliance.
Worked Example · 2026

A Real GBP 11,400 Conversion

A 28 m² single-storey rear extension in the Midlands, flat felt roof replaced with a prefabricated trussed pitched roof and concrete interlocking tiles:

  • Strip flat roof + dispose: GBP 900
  • Trusses, timber + wall plates: GBP 2,800
  • Felt, battens + concrete tiles: GBP 3,200
  • Fascias, soffits + guttering: GBP 1,100
  • Scaffolding: GBP 1,200
  • Labour + finishing: GBP 2,200

Total: GBP 11,400 inc. VAT — about GBP 407 per m² including scaffold, mid-range for a complex pitch with new fascias.

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FAQ · 2026

Pitched Roof Conversion Cost FAQs · 2026

In 2026 UK, converting a flat roof to a pitched roof costs roughly GBP 5,000 to GBP 9,000 over a garage or porch, and GBP 9,000 to GBP 15,000 over a single-storey extension - about GBP 200 to GBP 360 per square metre. The price depends on the span, the new roof structure (prefabricated trusses vs cut roof), tile choice, and whether the existing flat roof and wall plates can be reused.
Usually no. Replacing a flat roof with a pitched roof is generally Permitted Development provided the new ridge is no higher than the highest part of the existing roof and the materials are similar in appearance. Planning is required in conservation areas, on listed buildings, in Article 4 zones, or where the new roof would significantly raise the height. Building Regulations always apply.
A pitched roof sheds water far better than a flat roof, lasts 40 to 60 years versus 15 to 25 for most flat coverings, improves insulation and kerb appeal, and removes the recurring cost of flat-roof re-covering. It is one of the most reliable ways to cure a persistently leaking garage or extension roof.
A typical garage or single-storey extension flat-to-pitched conversion takes 1 to 2 weeks on site: 2 to 3 days to strip the flat roof and fix wall plates, 2 to 3 days to erect trusses or cut the roof, then felting, battening, tiling and finishing. Larger or complex spans with valleys take longer.
Use prefabricated trusses rather than a cut roof, keep the span simple with no valleys or dormers, choose concrete interlocking tiles over clay or slate, and reuse the existing wall plates and flat-roof joists where a structural engineer confirms they are sound. A simple garage conversion at this spec can land near GBP 5,000 to GBP 6,000 including VAT.
Often yes, both in value and saleability. Buyers and surveyors view a tiled pitched roof more favourably than a flat roof, and it removes a common mortgage-survey flag. On a garage or extension it typically returns its cost or better, and ends ongoing flat-roof maintenance.
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