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Everything you need to know about dormer loft conversions

4 min read
Oct '25 • by Heather

Quick summary

A dormer loft conversion typically costs around £20,000 to £40,000 for a 10-20 sqm space, including VAT, and takes roughly 8 to 12 weeks. It’s suitable for homes with pitched roofs and lofts, and most semi-detached houses can add one. Planning permission is usually not needed if it meets specific size and character rules, but building regulations must be followed.

It’s no secret that UK homes are facing a space shortage, especially in the high demand city areas. But with not enough new homes being built, and the cost of stamp duty forcing many to stay put, finding room for a growing family can be challenge.

It’s no wonder then that loft conversions have seen a huge upswing in recent years, Resi's own data shows a 94% increase in loft conversion enquiries in 2024, compared to the year before. Improving not moving is now the name of the game, and transforming the dead space in your loft is the ideal solution for many homeowners.

With the Stamp Duty tax hikes now in full force as of April 2025, we're likely to see this trend continue to curve steeply upwards.

If you are considering a loft conversion, you might have heard the phrase ‘dormer’ thrown about. But what is a dormer loft conversion? And, more importantly, is it right for your home? We asked our experts to reveal all...

What is a dormer loft conversion?

A dormer loft conversion is when a box shaped structure is added onto a pitched roof, creating walls that sit at a 90 degree angle to the floor. This helps to expand not only your headspace, but floorspace too.

Loft Conversion

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