Before you hire an architect
Extension and loft questions, answered
Short, honest answers for homeowners in Barnet, Camden, Haringey and across North London. These are general guidance, not a planning decision; rules change, so always check with your council. For a quick answer for your own house, try our planning permission checker.
How close to the boundary can I build an extension in Barnet?
You can build right up to the boundary, but under permitted development an extension within 2 metres of it can't have eaves higher than 3 metres. Building on or near the line usually also needs a Party Wall notice to your neighbour.
Barnet applies the same national permitted development rules as other boroughs, unless your house is in a conservation area or covered by an Article 4 direction. If the rules don't fit what you want, a planning application can still get approval. Check with Barnet Council for your address.
Can a neighbour stop my loft conversion in Camden?
A neighbour can't veto a loft conversion. If it needs planning, they can object and the council weighs that; a loft built under permitted development has no neighbour consultation. Under the Party Wall Act they can't block the work, only have it agreed properly.
Much of Camden is in conservation areas. In a conservation area, any loft extension that changes the roof shape needs planning permission. (Larger rear extensions under the prior approval route are different: neighbours are told and can comment.) A clear design and early contact with neighbours tend to reduce objections. Check Camden's planning pages for your street.
What is the maximum height for a permitted development extension or loft on a terraced house?
A single-storey rear extension can be up to 4 metres high, or 3 metres at the eaves within 2 metres of a boundary. A loft can't go above the highest part of the existing roof, and terraced houses get up to 40 cubic metres of extra roof space.
Rear extensions on terraced houses can go 3 metres deep, or 6 metres with prior approval, where the council tells your neighbours and they can comment. Dormers can't face the road, must sit at least 20cm back from the eaves, and side windows must be obscure-glazed and fixed shut below 1.7 metres. Flats, listed buildings, conservation areas and Article 4 areas have stricter rules.
Do I need planning permission for a rear extension in NW11 or Golders Green?
Often not: many houses in NW11 can extend at the rear under permitted development. Houses in Hampstead Garden Suburb or other conservation areas have fewer rights, and many need planning or other consent.
Our free planning checker gives a quick first answer for your house type and project. It's guidance, not a decision; for certainty you can apply for a Lawful Development Certificate.
Are there special rules in Hampstead Garden Suburb?
Yes. As well as council planning rules, most external changes need consent from the Hampstead Garden Suburb Trust, which has its own design guidance. The Suburb is also a conservation area, so permitted development rights are limited.
Plan for both approvals from the start, because a design that satisfies Barnet may still need changes for the Trust. Check the Trust's current guidance before you finalise a design.
Do terraced houses in Haringey have permitted development rights?
Many do, but parts of Haringey are conservation areas or covered by Article 4 directions that remove some rights. Check your exact address before relying on permitted development.
Haringey publishes its conservation area and Article 4 maps. If rights have been removed, a planning application is the usual route.
Can I see my extension in 3D before building?
Yes. We survey your home and build an accurate 3D model, so you can walk through the layout options before anything is fixed.
Seeing the space in 3D helps you decide on light, room sizes and how the extension links to the house, and avoids costly changes later.
What drawings does a builder need to price accurately?
Builders need technical drawings, not just planning drawings: construction details, structural information and a clear specification. Without them, quotes are guesses and costs tend to rise on site.
Our technical stage (RIBA Stage 4) produces drawings detailed enough for builders to price like for like and for Building Control approval.
Should I hire a RIBA Chartered architect or an architectural technician?
A technician can draw a simple extension. An architect also designs how the space works, where the light falls and what's likely to get planning. At DOR you deal with the RIBA Chartered principal throughout.
For straightforward permitted development work either can help. Architects add the most where design quality, planning risk or a sensitive area matter.
Planning an extension or loft?
Our house extension and loft conversion architects work across North London. Tell us about your home and see your indicative fee straight away.