Buying off-plan London property from Japan - construction milestones and guarantees

For Japanese buyers exploring London off-plan property developments, it is important to understand that the UK payment structure can vary by development. In Japan, a typical property purchase may involve a payment of around 10–20% at contract, with the remaining balance generally paid at settlement or delivery. Similarly, UK off-plan purchases commonly involve an initial reservation fee followed by a deposit on exchange, with the balance due on completion or tied to different construction milestones.

Some developments may involve payments spread across the construction period, but staged interim payments are not standard across all London developments. Therefore, as a Japanese buyer you should always check the specific payment schedule for each off-plan property development before committing.

How off-plan property payments work in the UK

Off-plan purchases in London generally move through four stages.

The reservation fee is a small sum, usually a few thousand pounds. You pay this fee to hold the unit while your solicitor reviews the contract. This is typically credited toward your deposit later. Under the New Homes Quality Code applicable to participating registered developers for reservations from 2 March 2026, buyers have at least a 14-day cooling-off period with a full reservation-fee refund. After that, permitted deductions may apply.

Once your solicitor has reviewed the contract and gives an approval to proceed, you pay the exchange deposit and the contracts are exchanged. The agreement drafted at the time of reservation will state the exchange deadline for the deposit. The deposit is usually around 10% and 20% of the purchase price, although some off-plan contracts require a larger deposit or additional staged payments.

Interim construction payments are not required by every developer. Some schemes ask for nothing further until completion; others tie additional staged payments to contractual dates and construction milestones. This can include a payment when the building reaches watertight stage. Your solicitor will update you with which structure applies before the exchange.

You pay the final balance at legal completion. You pay this amount when the building is finished and keys are handed over. For buyers remitting funds from Japan, this is the payment that needs the most lead time. Arrange overseas transfers and any mortgage drawdown in advance of the anticipated completion window. Once the property is ready, the developer will normally serve a notice to confirm the completion timetable.

Understanding off-plan construction milestones in London

Construction milestones help buyers understand how a development is progressing. They are not, however, necessarily the same as payment dates.

• Groundworks and foundations comprise site preparation and the substructure is laid.
• Superstructure is the frame that rises floor by floor. This is usually the longest visible phase.
• Watertight stage is when the building is enclosed and internal fit-out begins.
• A pre-completion snagging inspection may be carried out shortly before legal completion by the buyer or a suitably
• qualified property inspector. This checks the finish quality of the specific unit and identifies items that may require attention.
• During legal completion and handover, the final balance is paid, ownership transfers to the buyer and the keys are released.

Buyer guarantees when purchasing off-plan property from overseas

Buying a home that you cannot walk through carries obvious risks. UK new-build warranties exist specifically to address this.

The NHBC Buildmark warranty is one of the UK’s best-known and widely used new-build warranty schemes. It includes pre-completion deposit protection, followed by a two-year builder warranty period and eight years of NHBC insurance cover after completion. NHBC Buildmark warranty is typically 10% of the original purchase price, capped at £100,000, and applies to the first owner.

For the first two years after completion, the builder is directly responsible for putting right any defect that falls short of NHBC's technical standards. For the remaining eight years, NHBC's own insurance covers defined physical damage to the structure. This insurance is described by NHBC as insurance for physical damage caused by failure to build to NHBC requirements and is subject to the policy terms. The snagging inspection before completion matters for the same reason. It is an opportunity for homeowners to raise finish-quality issues while the builder still holds direct responsibility.

Why this structure works for buyers based in Japan

Two practical advantages stand out for remote buyers. The first is cash-flow planning. Where a development uses staged payments, capital commitments may be spread across the build period. Even where no interim payments apply, buyers generally have time between exchange and completion to prepare financing and plan international currency transfers.

The second advantage is price certainty. With an off-plan purchase, the price is fixed at the exchange itself and not at completion. However, since the price certainty is fixed in GBP and not in yen, the final price of purchase may change as per currency exchange fluctuations between exchange and completion.

For a complete walkthrough of the process, from reservation through to key handover, see our London property buying guide.

If you are considering a specific development and want help reading a payment schedule before you commit, talk to our Tokyo investment team.