What is an off-plan mortgage?
An off-plan mortgage is arranged for a property that has not yet been built, or is currently under construction, at the point of purchase. You reserve and exchange contracts based on plans and specifications, with completion - and mortgage drawdown - occurring when the property is physically finished. The time between exchange and completion is typically 6 to 24 months, and in some cases longer on large phased developments.
Why off-plan requires specialist lenders
Standard mortgage offers are valid for six months. Most off-plan purchases complete well beyond this window, meaning the offer expires before drawdown. Specialist new build lenders offer extended validity of 9 to 12 months and will in many cases extend further where a build is delayed due to circumstances outside the buyer's control. Without this provision, buyers must reapply at the end of the original offer period - at whatever rate is current at that time.
The reservation deposit
Off-plan purchases require a reservation deposit - typically £500 to £2,000 - paid to the developer to secure the plot. This deposit is usually non-refundable if you withdraw from the purchase. It is separate from the exchange deposit, which is paid when contracts are exchanged and is typically 5-10% of the purchase price. The reservation deposit does not protect against developer insolvency or project abandonment - understanding the developer's financial position is part of the due diligence process.
Key risks in off-plan mortgage lending
Off-plan purchases carry risks that do not apply to completed property, and lenders assess these carefully when underwriting.
Developer insolvency
If the developer becomes insolvent before completion, exchange deposits may be lost unless a deposit protection scheme or insurance policy is in place. Most solicitors advise on deposit protection as part of the conveyancing process. This risk does not affect the mortgage itself - the offer is only drawn down on completion - but it does affect the exchange deposit paid on contracts.
Market value at completion
The agreed purchase price is set at reservation, which may be 12 to 24 months before completion. If property values fall during this period, the completed property may be worth less than the purchase price. The mortgage lender will value the property at the point of completion, not the reservation price - and will lend against the lower of the two figures. This can require additional deposit at completion.
Build quality and specification changes
Developers sometimes alter specifications between reservation and completion - materials, layouts, or finishes may differ from the original plans. Any material change to the specification should be reviewed by your solicitor and may affect the mortgage if it materially changes the property value.
Offer expiry and rate risk
If the mortgage offer expires before completion and must be reissued, the new offer will be at whatever rate is available at the time of reapplication. This is a genuine risk in a rising rate environment. Some specialist lenders commit to honour the original rate on reapplication - confirming this provision at the application stage manages the risk.
Builder incentives and their effect on off-plan mortgages
Developers frequently offer incentives on off-plan purchases - cashback at completion, contributions to stamp duty or legal fees, free upgrades, or part-furnished specifications. Lenders require full disclosure of all incentives and deduct the value from the purchase price when calculating LTV. A 5% incentive on a £350,000 purchase reduces the lender's effective purchase price to £332,500, which changes the LTV calculation and may affect both the maximum loan and the rate tier. Incentives above 5% of the purchase price are treated particularly stringently by most lenders.
Deposit requirements for off-plan mortgages
Most specialist off-plan lenders require a minimum 10% deposit on new build houses and 15-25% on new build flats, reflecting the additional valuation and market risk. The exchange deposit - typically 10% of the purchase price - is paid at exchange of contracts, often 6 to 24 months before completion. Buyers must have the exchange deposit available as cash at exchange, separate from the eventual mortgage. Help to Buy alternatives and Shared Ownership schemes are available on new build off-plan purchases through a specialist lender panel.
Off-plan flats vs off-plan houses
New build flats face stricter mortgage criteria than houses. Maximum LTV on new build flats is typically 75-85%, with some lenders capping at 75% regardless of the borrower's profile. High-rise flats - generally defined as above a set number of storeys - have an even smaller lender panel and may require EWS1 cladding assessment certification before a mortgage can be offered. Off-plan houses, by contrast, are usually accepted on near-standard terms once the mortgage offer validity period is confirmed.
Why an off-plan mortgage needs a specialist broker
The off-plan mortgage market requires matching to lenders that actively want this business - not all lenders on the wider panel offer extended offer validity or are comfortable with developer risk. Applying to the wrong lender wastes time, leaves a hard credit search on your file, and risks the reservation timeline imposed by the developer. Doulton Bridging Finance identifies the lenders most appropriate for your specific off-plan purchase - property type, developer, location, LTV, and timeline - and manages the application to work within the developer's exchange deadline.