Understanding “Exchange of Contracts”, “Exchange on Notice”…

Buying or selling a home in England and Wales involves several key legal milestones. Two of the most important are the exchange of contracts and completion.

These stages mark the point at which the property deal becomes legally binding and when ownership finally transfers and understanding them can help you plan your move with confidence.

What Is the Exchange of Contracts?

The exchange of contracts is the moment in a property sale at which the transaction becomes legally binding.

Before exchange:

Neither the buyer nor the seller is legally obligated to proceed.
Either party can pull out without significant legal penalty (beyond losing an offer-deposit if one has been paid).

At exchange:

Contracts signed by both buyer and seller are formally exchanged between solicitors or conveyancers.
The transaction becomes legally binding for both parties.
The buyer usually pays a deposit (typically 5–10% of the purchase price).
A completion date is agreed and recorded in the contract.

Once exchange has taken place, if either party tries to pull out without contractual grounds, they can face financial penalties and legal action.

What Does “Exchange of Contracts on Notice” Mean?

In most standard property sales, the completion date is set at the time contracts are exchanged. However, with new build properties, it is often difficult to predict exactly when the property will be signed off by building control as complete.

In such cases, contracts may be exchanged “on notice”, meaning:

Contracts are exchanged before the exact completion date is known.
The developer (seller) agrees to give a set notice period, typically 10 days’ notice, of when completion will take place once the property is ready.
This method protects both parties: the buyer is legally committed, but the developer retains flexibility to complete the build.

The legal mechanic here allows the buyer to know that completion is coming, but only at a point when the property is truly ready, avoiding unnecessary delays.

Exchange of Contracts vs Completion: What’s the Difference?

Exchange of Contracts

Legal point of no return. Once contracts are exchanged, both parties must proceed to completion unless they have lawful grounds not to.
From this moment, risk in the property usually transfers to the buyer. For example, if the property were damaged before completion, the buyer generally remains responsible.

Completion

Completion is the stage where the full purchase price is transferred from buyer to seller via solicitors/conveyancers.
The buyer receives the keys and takes legal possession of the property.
The seller must vacate by the agreed time (often by 1pm on the day of completion).

How Long Is the Timescale Between Exchange and Completion?

There is no fixed legal timeline between exchange and completion, it depends on what the parties agree.

Typical timescales:

Same-day exchange and completion: possible (and increasingly common) when there is no chain (e.g., cash buyers).
Shortest practical gap: often between 1 and 7 days.
Typical gap: many transactions allow 7 to 28 days between exchange and completion to give time for moving arrangements.

For new build purchases with exchange on notice, the completion date is determined by the notice period once the property is signed off as complete.

Why Is There a Gap Between Exchange and Completion?

A gap allows:

Transfer of the balance of funds (especially where a mortgage is involved)
Coordination of moving arrangements, removals, utilities, and other logistics
Time for all parties to prepare for final handover of the property

The length of the gap may be influenced by:

Chain complexity (multiple linked sales)
Mortgage lender requirements
Buyer/seller availability and preferences

Practical Tips for Buyers & Sellers

For Buyers:

Ensure your mortgage offer and funds are lined up before agreeing a completion date.
Obtain buildings insurance from the point of exchange as once contracts are exchanged you are generally responsible for the property.
Understand that backing out after exchange can result in losing your deposit and potential litigation.

For Sellers:

Understand you are legally committed to sell after exchange and must deliver the property by completion.
If selling a new build, consider whether exchange on notice is appropriate for your timeline.

How Can Hegarty Help?

The exchange of contracts and completion are two distinct but essential stages in UK residential property sales. Exchange creates a binding legal obligation with a contractually agreed completion date, while completion is when the property changes hands and the buyer gets the keys.

In some situations, particularly with new build homes, exchange on notice is used to balance the need for legal certainty with the reality of construction schedules.

Understanding these stages, along with typical timescales, helps buyers and sellers make informed decisions and navigate their conveyancing process with confidence.

Contact our team today, for legal advice you can rely on.