How to buy a new-build home in London: the step-by-step process

Every stage of buying a new-build in London — from reservation and deposit to exchange, snagging and completion — and how long each takes.

By OpenHouse advisors · Updated 18 September 2026

The short answer

Buying a new-build in London follows a fixed sequence: choose a home, pay a reservation fee (typically £1,000–£5,000) to take it off the market, instruct a solicitor, exchange contracts within about 28 days paying a 10% deposit (sometimes staged), then complete when the home is built and pay the balance. For a completed home the whole process can take 6–12 weeks; for an off-plan home, exchange happens early but completion can be one to three years away.

Step 1 — Find and shortlist

London has dozens of live developments at any time. Decide your budget, bedrooms, area and whether you want to move in now (a completed home) or secure a future home at today's price (off-plan). A free advisor service such as OpenHouse compares every developer's live price list in one place, so you are not limited to a single developer's stock.

Step 2 — Reserve

When you choose an apartment you pay a reservation fee to the developer, which removes it from sale for an agreed period (usually 28 days) while your solicitor works. The fee is normally deducted from your purchase price at completion. Ask what happens to it if you withdraw — most developers refund it minus reasonable costs, but terms vary.

Step 3 — Mortgage and solicitor

Instruct a solicitor experienced in new-build conveyancing straight away, and get a mortgage decision in principle before you reserve. Note that most mortgage offers last six months, so for off-plan purchases completing further out you will typically re-apply nearer completion.

Step 4 — Exchange of contracts

You normally exchange within 28 days of reserving. At exchange you pay your deposit — usually 10% of the price, sometimes split (for example 5% at exchange and 5% six months later on off-plan schemes). Exchange is legally binding on both sides: the developer must deliver the home as specified and you must complete.

Step 5 — Build period, snagging and completion

For off-plan homes the developer gives an anticipated completion window and serves formal notice (usually 10–14 days) when the home is ready. Before completion you (or a professional snagging inspector) check the finish and list defects, which the developer fixes. On completion you pay the balance and get the keys. New homes come with a 10-year structural warranty (NHBC, Premier Guarantee or similar) and typically a two-year developer defects period.

Costs to budget for beyond the price

Stamp Duty Land Tax, solicitor fees, mortgage arrangement and valuation fees, a snagging survey, and — for apartments — the annual service charge and ground rent (new leases since 2022 have peppercorn ground rent). OpenHouse's advice is free; the developer pays our fee.

Frequently asked questions

How long does it take to buy a new-build in London?

For a completed home, typically 6–12 weeks from reservation to keys. For an off-plan home you usually exchange within 28 days of reserving, but completion can be one to three years later depending on the build programme.

How much deposit do I need for a new-build?

You pay a reservation fee (often £1,000–£5,000) first, then a deposit at exchange — normally 10% of the purchase price, sometimes staged on off-plan purchases. Your mortgage deposit may be higher depending on the lender.

Is the reservation fee refundable?

It is usually deducted from the price at completion. If you withdraw, most developers refund it less reasonable administration costs, but check the reservation agreement.

Do I pay a fee to use OpenHouse?

No. OpenHouse is free for buyers — we are paid by the developer — and you get the same price and availability as going direct, plus independent advice across every development.

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