Addendum to a Lease Agreement – When and How to Draft It
You’re sitting at the table with your tenant, the lease agreement in front of you, when suddenly a situation arises that you never addressed in the original document. Maybe you want to raise the rent, add a parking space, or allow a pet. “We can just agree verbally,” the other side says. But this is where legal nightmares begin – what’s agreed today might be denied tomorrow, and in court, only what’s in black and white will count.
This article is part of the large guide to lease agreements, where you can find more practical topics related to renting apartments, houses, and commercial spaces: read more
“Does an addendum to a lease always have to be in writing?” “Can we just confirm changes over email?” “What if we agree on a change but forget to sign it?”
In practice, I often see one big mistake: people believe that if they verbally agree, it’s just as valid as a written agreement. But with leases, the rule is simple: if it’s not in writing, it’s as if it never happened – and in some cases, the absence of an addendum can invalidate your arrangement entirely.
What You’ll Learn in This Article
When you must prepare an addendum to a lease agreement
What an addendum must contain
The most common mistakes when changing a lease
A real-life example from practice
When to Use an Addendum to a Lease Agreement
An addendum is used whenever you want to change or supplement any of the terms of a lease agreement – for example:
rent amount or service charges,
lease term (extension or shortening),
scope of use of the apartment or non-residential premises,
permission or prohibition of certain activities (e.g., subletting, keeping pets),
adding or removing furniture or equipment.
If you make the change verbally only, you risk the other party later claiming, “We never agreed to that,” and you won’t have proof.
What an Addendum Should Look Like
A properly drafted addendum must include:
Identification of the original lease (date, parties, subject of the lease).
Precise description of the change – what is being amended or added.
Effective date of the change.
Signatures of both parties – ideally on every page of the addendum.
The Most Common Mistakes
Changes communicated only by email without both parties’ signatures.
An addendum changes one clause but fails to address related provisions, creating contradictions.
Vague wording such as “the rent is adjusted” without specifying the new amount or date.
Real-Life Example
A landlord and tenant agreed over the phone that rent would increase by CZK 1,000 per month. The tenant paid the higher rent for several months, then returned to the original amount, claiming no agreement was ever made. Because the change wasn’t documented in a written addendum, the landlord had no chance to prove his version in court.
Lawyer’s Advice
Always put an addendum to a lease agreement in writing and keep it with the original contract. Even a small change can have a major impact on your rights and obligations.
Do you need to amend your lease and don’t want to risk legal disputes? I can prepare an addendum tailored to your situation that protects you – quickly, online, and for a fixed price.
Contact a legal professional – I specialize in contract law.
Learn more here.
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Addendum to a Lease Agreement – When and How to Draft It
Print You’re sitting at the table with your tenant, the lease agreement in front of you, when suddenly a situation arises that you never addressed