Planning
Planning Permission, Explained
Permitted development, conservation areas and party wall, in plain English.
Planning is often described as complicated. In truth, it is simply a set of rules that reward preparation. For most Surrey and London homeowners considering a loft conversion, there are three routes to understand — and each has a clear path through it.
Permitted development
Many loft conversions do not need full planning permission. Under permitted development, a rear dormer of up to 40 cubic metres on a terrace, or 50 cubic metres on a detached or semi-detached house, is generally allowed — provided it sits behind the front roof plane, does not exceed the highest part of the existing roof, and uses materials sympathetic to the house.
We recommend applying for a Lawful Development Certificate even when permission is not required. It is inexpensive, it takes eight weeks, and it removes any ambiguity for future buyers.
Conservation areas and listed buildings
Permitted development rights are withdrawn in most conservation areas and on all listed buildings. This does not mean a loft conversion is impossible — many of our most considered projects sit within conservation areas — but it does mean the design conversation begins earlier, and the planning route is a full householder application.
Pre-application advice from the local authority is almost always worth the fee. It gives you a view of the officer's thinking before the formal clock starts.
Party wall
If your loft shares a wall with a neighbour — as almost every terrace and semi does — the Party Wall etc. Act 1996 applies. Notice must be served at least two months before work begins on the shared wall.
Handled well, this is a courteous formality. Handled late, it can add weeks to a programme and needless friction to a good neighbourly relationship. We serve notices early on every project where they apply.
In summary
- Many loft conversions fall under permitted development — but apply for a Lawful Development Certificate anyway.
- Conservation and listed status remove PD rights; expect a full householder application.
- Pre-application advice is usually worth the fee.
- Serve party wall notices early — two months is the minimum.