New Build Homes in London

New Builds in London: What the Work Involves

Most new homes built in London by small contractors aren’t on open plots. They’re infill sites between existing houses, a bombed gap in a terrace that was never rebuilt, a garage court behind a row of houses, or an old bungalow knocked down and replaced. Every one of them has neighbours on at least two sides and a street that wasn’t designed for lorries.

The drawings show the house. They don’t show the sewer running under the garden, the tree roots in the London clay or the fact that a concrete pump can’t get round the corner. That’s where most of the time and money on a London new build goes.

Buildability before the start

A design can look right on paper and still be hard to build. A basement next to an old terrace needs underpinning or a piled wall, and both need the party wall process. A steel frame needs a crane or a lot of manual handling. A flat roof with no parapet detail leaks at the edges. Problems like these are far cheaper to sort out at the pre-construction stage, before the price and programme are fixed.

The planning permission matters too. Conditions often cover materials, landscaping, construction hours and a Construction Management Plan, and some have to be discharged before any work starts on site. Starting before a pre-commencement condition is discharged can leave the whole development without valid permission.

New dwellings in London also pay the Community Infrastructure Levy, both the Mayor’s and the borough’s. Self-builders can claim an exemption, but only if it’s claimed before work starts.

Building on an empty plot is the easy case. When there’s an old building to clear first, the council has to be told before demolition starts:

“No person shall begin a demolition to which this section applies unless— (a) he has given the local authority notice of his intention to do so, and (b) either— (i) the local authority have given a notice to him under section 81 below, or (ii) the relevant period (as defined in that section) has expired.”

Building Act 1984, section 80(2)

Copies of the notice go to the neighbours and the gas and electricity suppliers. The same section exempts very small buildings, with the limit given as “not more than 1750 cubic feet”, one of the few places a 1984 Act still measures in imperial units. In practice it means a shed or small garage.

London has controlled how houses are built for a long time. After the Great Fire of 1666, the Rebuilding Act required new houses in the City to be built in brick or stone. The London Building Act of 1774 sorted houses into four “rates” by size and value, each with its own minimum wall thicknesses. It’s part of the reason so many Georgian terraces look alike.

What sits behind the finish

A new build is judged by how it performs once people live in it. Most of that is in the shell: insulation, airtightness, structural detailing, sound between rooms, moisture control and ventilation.

Part L of the Building Regulations sets energy targets through SAP calculations, and every new dwelling has to pass an air pressure test before completion. A house that leaks air through service holes and badly taped membranes fails the test, and the fix means opening up finished walls. Ventilation has to be designed alongside the airtightness, because a very airtight house with no ventilation gets condensation and mould.

Security is a requirement only for new homes:

“Reasonable provision must be made to deter and resist unauthorised access to— (a) any dwelling; and (b) any part of a building from which access can be gained to a flat within the building.”

Building Regulations 2010, Schedule 1, Part Q1

That means front and back doors, ground floor windows and any easily reached windows have to be tested security products, usually to PAS 24. Bespoke timber doors made by a local joiner often haven’t been tested, which is a problem if they’re ordered before anyone checks. Part Q came in during 2015. Part S, which requires electric vehicle charge points for new homes with parking, came in during 2022.

Drains and water

Every new house needs a foul and surface water connection. The right to connect to the public sewer is set out in the Water Industry Act:

“Subject to the provisions of this section— (a) the owner or occupier of any premises, or (b) the owner of any private sewer which drains premises, shall be entitled to have his drains or sewer communicate with the public sewer of any sewerage undertaker and thereby to discharge foul water and surface water from those premises or that private sewer.”

Water Industry Act 1991, section 106(1)

The right exists, but the connection still has to be applied for with Thames Water, and the work on the road side has to be done to their standards. On many London sites surface water can’t go to the combined sewer at all, or only at a restricted rate, so the drawings include soakaways, attenuation tanks or a green roof. Building within three metres of a public sewer needs a build-over agreement too.

A new water supply is a separate application, with its own lead time. A temporary supply for the build is needed long before the permanent one.

London site logistics

Access decides a lot of the programme. A narrow street can mean small lorries only, deliveries in set hours, and a banksman for every one. Skips need a council licence, scaffolding on the pavement needs another, and parking bay suspensions need booking ahead. On a tight infill site, materials have to arrive in the order they’re used, because there’s nowhere to store them.

Neighbours are close. Piling and excavation near their foundations fall under the Party Wall Act, and the awards have to be agreed before that work starts. Most councils limit noisy work to weekday daytime hours and Saturday mornings.

Built for living in

A new home should still feel right in twenty years. That comes down to plain things: rooms in proportion, windows where the furniture won’t block them, enough storage, enough sound insulation between bedrooms and bathrooms, and details that age well. A rendered parapet with no coping drips black streaks down the wall within a couple of winters. A threshold with no fall lets rain in under the door.

Mortgage lenders usually want a ten-year structural warranty on a new home, from NHBC or a similar provider. The warranty provider inspects at key stages, so it has to be arranged before work starts.

Force Builders builds new homes across London, including Kensington, Knightsbridge, Wimbledon, Richmond, Archway, Finchley, Fulham, Notting Hill, Holland Park and Putney, and also works as high-end builders in London on refurbishments.

New Build Projects FAQ: Your Questions Answered (Honestly)

How much does a new build actually cost per square metre in London?

Roughly £2,500 to £4,500 or more per square metre, depending on the site, the specification and whether there’s a basement. A reliable figure needs the drawings and a site visit.

How long am I going to be dealing with a construction site?

For a one-off house, roughly 10 to 14 months on site, plus the time for drawings, planning and discharging conditions beforehand. Weather, inspections and deliveries on tight streets account for most of the variation.

Will you handle the “Party Wall” headaches?

Party wall notices and awards are handled by surveyors, and they have to be in place before work on or near the shared structure starts. The build programme has to allow for them.

Is it actually possible to build a “Net Zero” home in a tight London plot?

Yes, but it starts with the fabric: insulation and airtightness first, then a heat pump and solar panels. The Future Homes Standard pushes all new homes in that direction anyway.

What happens if the price of materials spikes mid-build?

Prices for the main materials are best fixed with merchants early. The contract should say how large price changes are handled, so neither side has to argue about it later.