Real Estate Contract Addendum Template for England and Wales

It's a written document that adds to, modifies, or clarifies one or more terms of an existing property sale contract without replacing the original contract. Under the Law of Property (Miscellaneous Provisions) Act 1989, any variation to a land contract must itself be in writing and signed by both parties to be legally effective.

In practice, both terms describe modifications to the original contract. An addendum typically adds entirely new terms (for example, an obligation to carry out specific works before completion), while an amendment changes an existing clause (for example, the completion date). Both must satisfy the same formality requirements: in writing and signed by both parties.

Common uses include: adding special conditions following a survey (for example, the seller agrees to remedy a specific defect before completion), incorporating the results of pre-contract negotiations that were not in the original contract, adjusting the purchase price after a structural survey or valuation, and recording an agreed extension to the completion date.

An email exchange can satisfy the 'in writing' requirement of the Law of Property (Miscellaneous Provisions) Act 1989 if both parties or their solicitors confirm the addendum terms and their agreement by email. However, some solicitors prefer a formal letter or pdf document signed by both parties to reduce ambiguity. The safer practice is a single signed document clearly referenced to the original contract.

Yes. If an addendum agreed after exchange increases the purchase price, the buyer's SDLT liability increases accordingly. Where the addendum is signed before completion, the SDLT return filed after completion should reflect the addended price. If completion has already occurred on the basis of the original price, an amended SDLT return must be filed with HMRC within 14 days of the addendum date.

An addendum to a land contract signed by only one party is not legally effective under the Law of Property (Miscellaneous Provisions) Act 1989. The original contract terms continue to apply. Buyers and sellers should ensure both parties' solicitors formally exchange signed copies of the addendum document before either party acts on its terms.

Yes. Agreeing a new completion date is one of the most common uses of a contract addendum. Without a written, signed addendum, either party could insist on the original completion date and treat the other as in default. The addendum should clearly state the new date, confirm that all other contract terms remain unchanged, and be signed before the original completion date passes.

The Land Registry receives the transfer deed (TR1), not the underlying sale contract or its addenda. However, the TR1 must reflect the correct consideration and transfer terms, which the addendum may have changed. The solicitor preparing the TR1 must use the addended figures, and any SDLT return submitted to HMRC must reflect the final agreed consideration after all addenda.