Loft conversions in North London
North London housing stock is unusually well suited to loft conversions, and it is mostly down to what was built here and when. Victorian and Edwardian terraces with steep roofs and rear outriggers, and 1930s semis with hipped side roofs, are two of the easiest property types to convert well.
We design and build loft conversions across Barnet, Haringey, Enfield, Islington, Camden and the surrounding areas. Drawings, structural calculations, Building Regulations and the build itself all come from one team.
What North London roofs will take
Victorian and Edwardian terraces. Common across Islington, Haringey, Hackney borders and much of inner North London. Steep roof pitches give good volume, and the rear outrigger, the back projection these houses were built with, makes them the right shape for an L-shaped dormer. That usually produces a double bedroom plus a separate bathroom rather than one room.
1930s semis. Dominant in Finchley, Barnet, Southgate and the outer boroughs. These typically have hipped roofs, where the side slopes inward and wastes internal volume. Squaring that off with a hip-to-gable recovers the space, and it is often combined with a rear dormer to open up the whole floor.
Period terraces with low head height. Where the existing height is poor but the roof is steep, a mansard is often the only conversion that produces a genuinely usable floor. More expensive, almost always needs planning permission, and the right answer when you are adding a storey rather than a room.
Post-war and modern housing. Trussed roofs, common from the 1960s onward, have W-shaped webbing running through the loft and each truss is carrying the roof. They convert, but the steelwork adds cost. Shallow pitches sometimes rule a conversion out entirely, and we would rather tell you that early.
Which conversion suits your house
| Your property | Usual conversion | What you gain | Typical cost |
|---|---|---|---|
| Victorian terrace with outrigger | L-shaped dormer | Double bedroom plus a bathroom | £65,000 to £85,000 |
| Victorian terrace, low head height | Mansard | A full extra storey | £70,000 to £95,000 and above |
| 1930s semi, hipped roof | Hip-to-gable with rear dormer | Bedroom with room for an en-suite | £60,000 to £80,000 |
| Terrace or semi, good head height | Rear dormer | A double bedroom | £50,000 to £65,000 |
| Any roof with 2.4m or more | Velux | One room, roofline unchanged | £40,000 to £50,000 |
Costs are 2026 London ranges and exclude VAT, professional fees and any en-suite. Full detail sits on the loft conversion cost page.
Planning permission in North London
Most rear dormers and Velux conversions fall under Permitted Development: 40 cubic metres of added volume on a terraced house, 50 on a semi or detached, nothing forward of the original roof slope facing a highway.
The complication in North London is conservation areas. Barnet, Haringey, Camden and Islington all have a significant number of them, and inside a conservation area Permitted Development rights are usually restricted. Some streets are also covered by Article 4 directions, which remove specific rights that would otherwise apply.
That does not mean a conversion is off the table. It means the application matters, and the design has to respect the roofline the council is protecting. A rear dormer that is invisible from the street is a very different conversation from a front dormer on a uniform terrace.
Practical first step: check whether your address sits in a conservation area on your council's website before you plan anything. If it does, budget eight to twelve weeks and £2,000 to £5,000 for a planning application.
Every conversion needs Building Regulations approval regardless of the planning route, covering fire escape, the staircase, floor loading, insulation and ventilation.
Areas we cover in North London
Barnet, Finchley, Whetstone, Southgate, Palmers Green, Enfield, Winchmore Hill, Muswell Hill, Crouch End, Highgate, Wood Green, Tottenham, Islington, Highbury, Camden and the surrounding areas.
We also work across East London and Essex, including Chingford, Brentwood and Romford.
How a North London conversion runs
Survey first. We measure the head height from ceiling joist to ridge, look at the roof structure, and check what the staircase below will allow. That determines which conversions are genuinely available to you.
Design and structure together. Architectural drawings and structural calculations are produced in-house, so the design submitted to Building Control is the one that gets built.
Approvals. We handle Building Regulations on every project and the planning application where one is needed. On terraced and semi-detached properties we also handle party wall notices, which most North London conversions require.
Build. One team, one project manager, a fixed price agreed before work starts, and payments tied to stages of work rather than dates.
Loft conversions in North London: frequently asked questions
How much does a loft conversion cost in North London?
Between £40,000 and £95,000 in 2026 depending on type. A Velux starts around £40,000, a rear dormer runs £50,000 to £65,000, and a mansard £70,000 to £95,000 or more.
Do I need planning permission in a North London conservation area?
Usually yes. Conservation area status normally restricts Permitted Development rights, and some streets carry Article 4 directions that remove them further. Check your address on your council's website before planning the work.
Which loft conversion suits a 1930s semi?
Often a hip-to-gable, sometimes combined with a rear dormer. The hipped side roof on these houses wastes internal volume, and squaring it off recovers the space.
Which loft conversion suits a Victorian terrace?
Usually an L-shaped dormer, which wraps around the rear outrigger and typically produces a bedroom plus a bathroom. Where head height is poor, a mansard may be the better option.
How long does a loft conversion take in North London?
Four to six weeks on site for a Velux, six to eight for a rear dormer, ten to sixteen for a mansard. Add design time, and eight to twelve weeks more if planning permission is needed.
Thinking about converting your loft?
Tell us your address and what you want the space to do. We will come back with the conversions your roof will take, a realistic cost range, and a straight answer on whether your street's conservation status is going to matter.
