If you’re building an extension, replacing a garage roof, or considering a full roof replacement, one of the first decisions is: flat or pitched? Both have pros and cons. Here’s what 30 years of roofing experience across East Anglia has taught us.
Flat Roof: Pros and Cons
**What is a flat roof?** Technically, flat roofs aren’t completely flat—they have a slight gradient (1-3 degrees) to allow water drainage. Common materials include EPDM rubber, GRP fibreglass, and traditional felt.
Advantages:
✓ **Lower upfront cost** — Flat roofs typically cost £40-£80 per m². For a small extension (15m²), that’s £600-£1,200 vs £1,500-£2,500 for pitched.
✓ **Easier to install** — No complex framework, faster installation, less labour cost.
✓ **Usable space** — Modern flat roofs can be walked on (roof terraces, green roofs, solar panels).
✓ **Good for extensions** — Perfect for single-storey rear extensions where height is limited.
Disadvantages:
✗ **Shorter lifespan** — EPDM lasts 25 years, GRP 20-25 years, felt 10-15 years. Pitched roofs last 50+ years.
✗ **Ponding issues** — Poor drainage leads to standing water, which accelerates wear and causes leaks.
✗ **More maintenance** — Requires inspection every 2-3 years to check for cracks, blistering, or seam failures.
✗ **Less insulation space** — Harder to achieve high U-values for energy efficiency.
Pitched Roof: Pros and Cons
**What is a pitched roof?** Any roof with a slope greater than 10 degrees. Common materials include concrete tiles, clay tiles, slate, and metal sheets.
Advantages:
✓ **Long lifespan** — Slate lasts 80-100 years, clay tiles 60+ years, concrete tiles 50+ years.
✓ **Better drainage** — Water runs off quickly, reducing leak risk.
✓ **Higher property value** — Buyers prefer pitched roofs for main dwellings—they look better and last longer.
✓ **More insulation space** — Easier to meet Building Regs thermal efficiency standards.
✓ **Lower maintenance** — Inspect every 5 years, replace damaged tiles as needed.
Disadvantages:
✗ **Higher upfront cost** — Pitched roofs cost £60-£120 per m² including framework. Full house roof: £5,000-£8,000.
✗ **Complex installation** — Requires skilled labour, takes longer, needs scaffolding.
✗ **Height restrictions** — Planning permission may be needed if you’re adding height to an extension.
Cost Comparison (2025 Prices)
Small Extension (15m²)
– Flat (Felt): £600-£900 | Lifespan: 10-15 years – Flat (EPDM): £900-£1,200 | Lifespan: 25 years – Flat (GRP): £1,000-£1,350 | Lifespan: 20-25 years – Pitched (Concrete tiles): £1,500-£2,500 | Lifespan: 50+ years
Full House Roof (80m²)
– Flat (Felt): £3,200-£4,800 | Lifespan: 10-15 years – Flat (EPDM): £4,800-£6,400 | Lifespan: 25 years – Pitched (Concrete tiles): £5,000-£7,000 | Lifespan: 50+ years – Pitched (Slate): £7,000-£10,000 | Lifespan: 80-100 years
Lifespan & Maintenance Comparison
Flat Roofs:
– Traditional felt: 10-15 years (requires re-coating every 5 years) – EPDM rubber: 25 years (minimal maintenance) – GRP fibreglass: 20-25 years (occasional resin top-up) – Inspection: Every 2-3 years
Pitched Roofs:
– Concrete tiles: 50+ years – Clay tiles: 60+ years – Natural slate: 80-100 years – Inspection: Every 5 years – Maintenance: Replace damaged tiles as needed
Which Should You Choose?
Choose a Flat Roof if:
– You’re building a small extension and want to keep costs down – Height restrictions prevent a pitched roof – You want a roof terrace or green roof – You’re covering a garage or outbuilding – You’re willing to accept a shorter lifespan for lower upfront cost
Choose a Pitched Roof if:
– You’re replacing your main house roof – You want the longest possible lifespan – You prefer traditional appearance – You want to maximise property value – You’re willing to invest more upfront for lower long-term costs
East Anglia Considerations
In East Anglia’s climate, pitched roofs generally perform better on main dwellings due to:
– Heavy rainfall requiring good drainage – Wind exposure (especially coastal areas) – Traditional architectural styles – Long-term value in the property market
However, flat roofs work well for:
– Modern single-storey extensions – Garages and outbuildings – Properties where planning restricts height – Budget-conscious projects
Cost Per Year Analysis
Example: 15m² Extension
**Flat Felt Roof:** – Upfront: £750 – Lifespan: 12 years – Cost per year: £62.50
**Flat EPDM Roof:** – Upfront: £1,050 – Lifespan: 25 years – Cost per year: £42
**Pitched Concrete Tile:** – Upfront: £2,000 – Lifespan: 50 years – Cost per year: £40
Over the long term, pitched roofs often work out cheaper per year despite higher initial costs.
Building Regulations
Both flat and pitched roofs must meet Building Regulations for:
– Thermal performance (U-values) – Fire safety – Structural integrity – Drainage – Ventilation
Flat roofs typically need more insulation thickness to achieve the same U-value as pitched roofs due to limited depth.
What You Get with Met-all Roofing
Whether you choose flat or pitched, we provide:
– Free site survey and advice – Detailed quotes comparing options – Building Regs compliance – Quality materials from trusted manufacturers – 12-month workmanship guarantee – 30 years’ experience across East Anglia
Call 01603 361162 for expert advice on flat vs pitched roofs
Conclusion
For main house roofs in East Anglia, pitched roofs are usually the better long-term investment—they last 50-100 years and add property value. For extensions and outbuildings, flat roofs make economic sense if you choose quality materials like EPDM.
The decision depends on your budget, building type, and how long you plan to stay in the property. We’ll help you weigh up the options based on 30 years of local experience.