Guide · 30 October 2026

Building costs and house prices in Haringey

Haringey stretches from Highgate and Muswell Hill in the west to Tottenham and the Lea Valley in the east, and the two halves feel like different property markets. The west has big Edwardian houses on hilly streets; the east has long Victorian terraces, many of them long since divided into flats. That split shapes almost every answer below, from what a bigger home costs to which planning rules apply to your street.

The Census 2021 accommodation-type table (TS044, via Nomis) counted 105,092 households in the borough. 35.4% lived in purpose-built flats and 22.8% in a flat carved out of a converted or shared house, roughly double London’s 11.1%. Terraced houses held 25.6% of households, semis 9.4% and detached houses 3.9%. Put together, about 39% of households here live in a whole house, against 46% across London.

What homes cost in Haringey in August 2026

The UK House Price Index from HM Land Registry and the ONS, published on 21 October 2026, gives Haringey an average price of £633,221 for August 2026. The figures are provisional. Prices were 1.4% lower than a year before and slipped 0.2% on July, a slightly gentler fall than London’s 2.2%. The London average was £554,430, so a typical Haringey home costs about £79,000 more, and the borough sits 9th of 33 on price. The high point was £646,216 in March 2026, only about 2% above today’s level. First-time buyers paid £534,079 on average, and people who had owned before paid £801,772.

Houses held their value while flats fell, which widens the gap for anyone hoping to move up. The detached figure, more than double London’s, needs a strong warning: fewer than one home in 25 here is detached, most of them in the dearest western streets, and the HPI models type averages rather than simply averaging the few that sell. Land Registry recorded 100 sales of all types in the borough in June 2026, the latest month with a count. The data comes from the HPI full file and the ONS local house prices page for Haringey. These are borough-wide averages that mix Highgate with Northumberland Park, so they will be revised and can’t value a particular home.

Move to a bigger home, or build?

On August’s averages, stepping from a flat to a terraced house meant finding about £332,000 more, and from a terrace to a semi about £435,000 more. The semi-to-detached step came to roughly £1.2 million, but that rests on very few sales and shouldn’t be relied on. Stamp duty, legal fees, surveys and removals come on top of each figure.

Nobody publishes building costs for Haringey alone, so the figures below are national. Checkatrade’s house extension cost guide (updated June 2026, with estimates checked by RICS and CIOB members) gives these UK ranges, excluding VAT:

• £1,800–£3,000 per m² for a finished single-storey extension
• £30,000–£42,000 for a 15m² rear extension to a mid-terrace house
• £108,000–£180,000 for a 60m² two-storey extension
• £50,000–£95,000 for a 30m² loft conversion
• £100,000–£160,000 for a 40m² basement
• £350–£950 for architectural drawings

Checkatrade says its figures don’t reflect location and that London and the South East usually cost more, so expect local quotes above these ranges, and add VAT. Even allowing for that, a loft or a modest rear extension on a terrace costs a fraction of the £435,000 needed to swap it for a semi, which is why so many Haringey owners stay and build. Flat owners are in a different position. Flats have no permitted development rights, nearly any change outside the flat’s own walls needs planning permission, and leaseholders usually need the freeholder’s written consent as well. For them, moving is often the only realistic way to gain much space. Either way, don’t assume you’ll get the building cost back on sale; judge the work on whether it gives you the room you need.

Permitted development: the national rules

For houses, the Planning Portal’s extension guidance sets out what can be built without an application. A single-storey rear extension can project 3 metres from the original back wall of a terrace or semi, or 4 metres for a detached house. Under the prior approval scheme, where the council consults the neighbours first, those limits rise to 6 and 8 metres. A single-storey side extension can be up to 4 metres high and half the width of the original house. The loft conversion guidance allows up to 40 cubic metres of extra roof space on a terrace and 50 cubic metres on other houses, with nothing built out from the roof slope facing the road.

Those rights are narrower in conservation areas, where side extensions, rear extensions of more than one storey and dormers fall outside permitted development, and on streets with Article 4 directions (see below). If your plans do fit, a Lawful Development Certificate from the council gives you proof for a future buyer. Building regulations approval is needed whichever way you go.

How Haringey judges extensions

Applications are decided against the London Plan and Haringey’s Local Plan. Its Strategic Policies date from 2013, with alterations adopted on 24 July 2017, and the Development Management Policies were adopted the same day. Policy DM12 on housing design covers house extensions. In short:

• Stay subordinate. An extension should be smaller than the original house and respect the rhythm of the terrace or street it sits in.
• Rear extensions. Full-width rear extensions are not normally acceptable, and an extension should sit below the main roof ridge.
• Dormers. Dormers belong at the back. Front dormers are not normally allowed.
• Guidance. Applicants are expected to follow the council’s supplementary planning documents (SPDs), including the one for South Tottenham.

That South Tottenham document is unusual. The House Extensions in South Tottenham SPD, revised in October 2013, exists because many large families there need more bedrooms, and it sets out three approved roof extensions for single-family houses in its area: a full-width rear dormer no higher than the ridge, a whole extra floor with a flat roof behind a parapet, or a full second floor with loft rooms in a new pitched roof. The third is the maximum the council will accept. The summary leaflet asks for matching materials and windows that copy the floor below, and points out that neighbours who build at the same time can share the cost of strengthening the party wall between them. If you live in or near N15 or N16, check the area map before asking anyone to draw a roof.

A new Local Plan is in preparation. Its draft went out for consultation from 10 October to 19 December 2025 and drew more than 10,000 responses, and the council expects to publish the final version in the second half of 2026. Until a new plan is adopted, the 2017 policies apply.

Conservation areas and Article 4

When the Development Management Policies were adopted in 2017, Haringey had 28 conservation areas, along with 471 listed buildings and about 1,150 locally listed ones. They range from Highgate, Muswell Hill and Crouch End to the Tottenham High Road corridor and planned estates such as Noel Park and Tower Gardens. Check your address on the council’s conservation areas pages, which also explain what needs permission inside them.

The council’s Article 4 directions page lists several kinds. Noel Park, Peabody Cottages and Tower Gardens have had directions in force since 21 December 2020, and an older one still covers Rookfield Estate, bringing details such as windows, doors, roofs and front boundaries under planning control. Separately, since 30 November 2013 a direction has removed the right to turn a family house into a small house in multiple occupation without permission across most of the east of the borough, including Tottenham, Seven Sisters, Noel Park, Harringay, Bounds Green and Woodside wards. Other directions protect employment sites rather than homes.

Basements

The Planning Portal says a new basement is likely to need planning permission. Haringey’s policy DM18 asks applicants to show the work won’t harm the stability of their own or neighbouring buildings, won’t worsen flooding, and won’t damage the street’s character, neighbours’ amenity or trees, with enough soil left over any part under a garden. Every application needs a Basement Impact Assessment by independent assessors, paid for by the applicant. Lightwells should take up no more than half the front garden, and bedrooms or living rooms in a basement in a flood-prone area need a safe way out. The council has also identified nine critical drainage areas at higher risk of surface water flooding, so check your address on the government flood map for planning early.

Party walls

In a borough of terraces and semis, most lofts, rear extensions and basements touch the Party Wall etc. Act 1996. Cutting steel beams into a shared wall, building on the boundary or digging near a neighbour’s foundations all mean serving notice first, and in a converted house that can include the flats above and below. GOV.UK’s party wall guidance explains the notices and time limits. If a neighbour doesn’t agree, one agreed surveyor, or one for each side, draws up an award setting out how the work will be done, usually paid for by the person building. Talking to neighbours before any paperwork lands tends to make the whole thing quicker and cheaper.

How to avoid a rogue builder

Be cautious with anyone who turns up uninvited, presses you to agree on the day, wants a big cash payment before starting or offers one round figure with no breakdown. A sound firm gives an itemised quote and a written contract, asks for staged payments as work is done, shows you its insurance and earlier jobs, and is clear about who arranges building regulations sign-off.

Look for registered firms through TrustMark, work through Citizens Advice’s checklist before building work, and report rogue traders to your local Trading Standards office.

Figures change: get quotes before you decide

House prices here are UK HPI figures for August 2026, published on 21 October 2026. They are provisional and will be revised, and September’s figures are due on 18 November 2026. Building costs are Checkatrade’s national ranges, last updated in June 2026; they aren’t local prices, and London work usually costs more. Household figures come from Census 2021, taken on 21 March 2021. Planning details come from Haringey’s 2017 Local Plan documents, the 2013 South Tottenham SPD and the council’s web pages as they stood when we checked them on 30 October 2026, and they will change when the new Local Plan is adopted. Check the rules for your own address, and get at least three itemised quotes based on proper drawings before choosing between building and moving.

Sources: UK House Price Index England: August 2026 (GOV.UK); UK HPI data downloads, August 2026 (full file, Haringey E09000014); ONS local house prices: Haringey; Census 2021 TS044 accommodation type (Nomis); Checkatrade: house extension costs; Planning Portal: extensions; Planning Portal: loft conversions; Planning Portal: basements; Haringey Council: Local Plan Strategic Policies; Haringey Council: Development Management DPD; Development Management Policies 2017 (PDF); House Extensions in South Tottenham SPD; South Tottenham SPD summary (PDF); Haringey Council: draft Local Plan; Haringey Council: conservation areas; Haringey Council: Article 4 directions; GOV.UK flood map for planning; GOV.UK: Party Wall etc. Act guidance; TrustMark; Citizens Advice: before building work; GOV.UK: find local Trading Standards. Data checked 30 October 2026.