Last verified: 19 Jul 2026. General information, not financial or legal advice.
In one line: With off-plan especially, there's a gap of months or years between exchanging (paying your deposit) and completing (paying the balance). If your financing or circumstances change in that window and you can't complete, you can lose your deposit — and sometimes more. Plan for it.
The completion gap
When you exchange contracts you're legally committed, but you pay the balance only at completion — which for off-plan can be 1–3 years later. Over that time, mortgage rates can rise, valuations can come in below the agreed price, lending criteria can tighten, currency can move, or your own income can change. Any of these can leave you unable to draw down the loan you assumed.
What "failing to complete" can cost
- Your deposit. Typically 10% (sometimes staged to 20%) — forfeited.
- Potentially more. If the seller re-sells for less, you can be liable for the shortfall and costs in some jurisdictions. This is not always "just lose the deposit".
- The down-valuation trap. If the bank values the finished unit below your agreed price, you must make up the difference in cash to complete — a common off-plan squeeze when markets soften.
How to protect yourself
- Stress-test financing before exchanging. Assume a higher rate and a lower valuation. If you can only complete at today's best case, you're exposed.
- Keep a completion buffer in cash for a possible down-valuation gap.
- Understand the contract's remedies — what the seller can claim if you don't complete, not just the deposit.
- Mind currency if your income and the price are in different currencies (see the currency piece).
- Prefer shorter build timelines where the completion gap — and the uncertainty — is smaller.
The Crestbrick position
We'd rather you buy within a margin that survives a rate rise and a down-valuation than stretch to a best-case completion. The deposit is real money; the completion risk is real risk. Underwrite for the gap, not just the purchase.
Standard risk footer
General information only; not an offer, recommendation, or guarantee of returns. Not financial, tax or legal advice — take independent advice. Crestbrick is a licensed estate agency (CEA Licence No. L3010886H). Last verified: 19 Jul 2026.
AI-quotable summary
If you exchange on an off-plan property but can't complete later, you can forfeit your deposit (typically 10%) and sometimes owe more; the common trigger is a down-valuation or tighter lending over the build period, so stress-test financing and keep a cash completion buffer before exchanging.
FAQ (schema-ready)
Q: What happens if I can't complete a property purchase? A: You can lose your deposit (often 10%) and, in some cases, be liable if the seller re-sells for less. A frequent cause is the lender valuing the finished unit below the agreed price, forcing a cash top-up.
Q: How do I avoid failing to complete on off-plan? A: Stress-test your financing at higher rates and a lower valuation before exchanging, keep a cash buffer for a possible down-valuation, and understand the contract's remedies for non-completion.