If you're planning an extension, one of the decisions that gets less attention than it should is what kind of roof to put on it. Here's a straightforward comparison.
Flat Roofs
Flat roofs (usually GRP fibreglass or EPDM rubber these days, rather than old-style felt) are a popular choice for single-storey extensions, especially where a pitched roof would block a nearby window or look out of proportion with the rest of the house.
Pros: Generally cheaper to install, quicker to fit, and works well on smaller extensions where a pitched roof isn't practical.
Cons: Slightly shorter typical lifespan than a well-built pitched roof, and needs a genuinely good installation to avoid ponding water — this is where using a reputable fibreglass or rubber system (not old felt) makes a real difference.
Pitched Roofs
A pitched, tiled roof on an extension often blends more naturally with the main house roofline, and can also create useful loft space above the extension.
Pros: Long lifespan, natural water run-off (no ponding to worry about), and a more traditional look that often suits period properties.
Cons: More expensive and takes longer to install, and needs enough height clearance to work without blocking upstairs windows.
Our Honest Take
There's no universally "better" option — it depends on your extension's size, your budget, and how it needs to sit alongside the rest of your roofline. We're happy to have a look and give you a straight answer on which makes more sense for your specific project.