In 2025 the average cost of a loft conversion in London is between £45,000 and £90,000. Most Londoners convert an attic into a dormer because it adds extra space and light. A loft conversion is a great way to add extra space to your home and increase the value of your property. A loft conversion is the type of construction work that requires a lot of planning and preparation. Cost is one of the things you need to consider before converting your attic.
Type of conversion
Type of roof
Type of windows
Number of windows
Size of the project
Fixtures and textures
Nature of the exterior
Client’s custom requirements
Location
To ensure you meet a realistic budget, you need to consider professional fees. These fees include planning fees, which are payable to the local council for planning permission, as well as design fees for architectural plans and structural calculations. Additionally, if the loft conversion involves work on shared walls, you may need to pay party wall fees to ensure that the work doesn't adversely affect your neighbours. Finally, building control fees are charged by the local authority to ensure the conversion meets the required building regulations.
If you want to know exactly how much a loft conversion costs in London you will need to get a quote from a London loft conversion specialist. If it is not your property then the average cost of a loft conversion varies between £45,000 and £90,000 depending on your requirements. A basic (small) conversion is the cheapest option. Even with a budget of £30,000, you will be able to get a small loft converted if you are willing to compromise the quality of work or there isn't much structural work involved.
The dormer conversion is the most popular. This project consists of an extension of the existing roof. The extension projects vertically and results in more floor space and headroom. A horizontal ceiling caps the extension inside. These conversions work well on many styles of homes, including detached houses, semi-detached houses, terraced, and end-of-terrace homes.
These loft conversions are usually built to the rear side of the house, but it can also be built on the side or as windows dormers. Dormer loft conversion costs between £32,000 and £50,000 on average, excluding dormer windows cost and VAT.
This type of extension originated with French architect Francois Mansard in the 1600s. In this design, the roof is flat, and the back wall slopes inwardly at an angle of 72 degrees. This steep angle allows for the maximization of the space available in your loft. For this type of loft conversion in West London, you may need to get planning permission. The Mansard loft conversion will cost £45,000 and upwards, depending upon the size and your requirements.
Hipped roofs, with their sloping sides, have limited useable space directly beneath them. Rebuilding a slanted hipped roof to one with flat-end gables opens the loft/attic area. This type of conversion changes the profile of the roof, so planning permissions are almost always required. A hip to gable loft produces satisfying under-roof space and, often, enough room for a staircase.
The cost of the hip to gable extension will be anywhere from £42,000 to £50,000 depending on the full specification of the property. This price will vary depending on the location of the property, it’s size, and other things. This price is inclusive of gable end window cost. You will get an accurate price quote once you get in touch with us and our specialist examines your property.
Adding an L-shaped dormer loft conversion is one of the best ways to increase the space and value of your property, whether you wish to extend the house for your growing family or to create some extra income. L-shaped loft conversions are a sensible and often fairly affordable way to add that extra space along with value to your property. With successful layout arrangement and beautiful design, your loft could be transformed into a comfortable living space to capture space and light. The cost of an L-shaped loft conversion in London can range from £35,000 to £75,000, but can be higher depending on the project.
Velux is also called a rooflight or skylight conversion. Velux is one of the most affordable extension options because no alterations are made to the roof. This also means that generally, no planning permissions are required. The main feature in this build is the addition of large windows installed flush with the roofline. Velux is a popular window manufacturer.
During this type of loft conversion, Velux windows are added to allow natural light to come in, which is very important for smaller spaces like this type of loft. The costs are also low for this conversion because loft generally doesn’t require planning permission for this conversion. Skylight or Velux conversion can be carried out on as little as £30,000.