Dormer Loft Conversions London

The cost of a dormer loft conversion in London varies based on size, specification and location, but most Prime Loft dormer projects fall within the range of £35,000–£65,000 fully inclusive — covering design, planning, structural engineering, all labour and materials, and your 10-year warranty. Contact us for a free, fixed-price survey specific to your property.

Most dormer conversions qualify as Permitted Development — meaning they do not require full planning permission. However, properties in conservation areas, listed buildings, or certain London boroughs may be subject to additional restrictions. Our planning team will assess your specific property before you commit to anything.

Research consistently shows that a well-executed dormer loft conversion adds between 15–25% to the value of a London home. In practical terms, adding a bedroom and en-suite typically adds £30,000–£80,000 in value depending on your area — making it one of the best returns on investment available to London homeowners.

Most Prime Loft dormer conversions take between 6 and 8 weeks on site from the start of construction. The preceding design and planning phase typically takes 6–10 weeks. We provide a detailed programme before work starts so you know the exact timeline.

In the vast majority of cases, no. Our teams are experienced at working around occupied households, and we schedule the most disruptive stages — such as roof opening — to be completed as quickly as possible. We always discuss your specific circumstances before work begins.