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20 February 2026

Flat Roof vs Pitched Roof — Which Is Right for Your Extension?

One of the first decisions you'll face when planning a home extension in Dublin is what type of roof to put on it. Flat roofs and pitched roofs each have their place — and the right choice depends on your budget, your planning situation, and how the extension will be used.

Flat Roofs

Modern flat roofs are a far cry from the leaky felted roofs of the 1970s. Today's GRP fibreglass or EPDM rubber systems can last 25 years or more with minimal maintenance.

Advantages: Lower cost, simpler construction, faster to build, can double as a usable roof terrace if properly specified.

Disadvantages: Require good drainage design to avoid ponding water. Some planning authorities in Dublin prefer pitched roofs for extensions visible from the street.

Pitched Roofs

A pitched roof on an extension typically means matching the angle and materials of your existing roof, creating a more seamless look from the outside.

Advantages: Better long-term weather performance, more visually consistent with the main house, often preferred by Dublin City Council planners.

Disadvantages: Higher cost and longer build time. Reduces usable headroom inside the extension if the pitch is steep.

Our Recommendation

For rear extensions where planning is more straightforward, a flat roof with a quality membrane system is often the most cost-effective choice. For side extensions or any work visible from the front of the property, a pitched roof matching the existing house is usually the safer planning bet.

Not sure what's right for your project? Call Dublin Roofing Pros on 01 234 5678 for a free consultation.

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