Yes. Class B is withdrawn entirely on designated land, which includes conservation areas, National Parks, the Broads, National Landscapes and World Heritage Sites, so even a rear dormer needs a planning application.

On Resi's own tendered figures, yes. A main dormer conversion comes in at £60,000 to £80,000 excluding VAT against £70,000 to £110,000 for a single storey rear extension. The trade off is that a loft gives you the space the roof happens to have, where an extension lets you choose. Single storey extension cost has the comparison.

A standard rear extension in London usually runs between £2,800 and £4,400 per square metre. For identical projects in the North East, expect figures around £2,200 to £3,450 per m². Side infills carry the highest rate per unit area, coming in at £3,900 to £5,000 per m² across London.

Usually. Adding kitchen and living space is one of the more reliable ways to do it. Whether it adds more than it costs is a local question, because every street has a ceiling price that buyers will not go above however good the house is. The way to find out is to ask two or three estate agents who sell on your road what your house is worth now and what it would be worth with the extension built.

A party wall is a wall you share with the house next door. If your work affects one, your neighbour can appoint their own surveyor, and the person doing the building work normally covers the reasonable cost. The exact amount is settled in the formal agreement rather than fixed in advance. How close can you build to your neighbour's boundary explains the process.

Not legally, but you do need drawings a builder can price and build from, and calculations from a structural engineer for the steels. That can come from an architect, an architectural designer or a specialist loft company. Whoever you use, check them properly: experience with loft conversions, work you can actually look at, and a solid Trustpilot rating.

Usually. A bedroom and a bathroom is one of the more reliable ways to do it, though a local estate agent will tell you what it’s worth in your area.

If you’re looking to add more value to your home, it can be helpful to reach out to a local estate agent to find out what position you’re starting from. You can then work with our team to uncover your project options, as well as get a view of what may be your best bet for increasing the return on your investment.

1. Finance
2. Measured surveys
3. Home design
4. 3D models and interactive walkthroughs
5. Planning submission
6. Party wall surveys
7. Structural engineering
8. Building regulations

At the start of your project, our team will come to conduct a measured survey of your home. We use commercial grade lasers, rather than traditional hand methods, to create a digital twin of your property. This can then be turned into your existing drawings, as well as be referenced by our team throughout the process, meaning no further visits should be necessary.

1. Your name, contact details and the address of the property in question
2. Basic information about the property
3. Your preferred style, estimated budget and a brief description of what you are looking to achieve
4. Your expectations on timings
5. Uploads of floor plans, inspiration or existing photos of the property (all optional)

Each project is different, but there are some common factors that will affect the cost of your London extension.

• Size
• Complexity
• What part of your home you want to extend
• Your property type
• Type of rooms you’re looking to add/expand

To discover the cost of your potential extension, you can get a quote in minutes here. Otherwise, for tailored prices, we recommend booking a consultation with your prospective architect.