You Are the Client Dutyholder: What the Building Safety Act Put on London Homeowners

On 1 October 2023 the law made you a dutyholder on your own building work. Not a metaphor — a defined role in the Building Regulations, with 3 duties attached. Most homeowners have never been told, because the reform that created it arrived wrapped in headlines about tower blocks that have nothing to do with a house in London.

The short version

The Building Safety Act 2022 is the post-Grenfell reform, and most of what it contains is aimed at tall residential buildings. One part of it is not. The Building Regulations etc. (Amendment) (England) Regulations 2023 created dutyholder roles for all building work in England, from 1 October 2023.

If you are the person having the work done, you are the client. That is you, on your extension.

The duties are proportionate. They are also real, and nobody sends you a letter about them.

Key takeaway

The Gateways you have read about apply to higher-risk buildings — at least 18 metres or 7 storeys, with at least 2 residential units. Your house is not one. The dutyholder duties are a different part of the same reform, and those do apply to you.

What actually changed, and what did not

The confusion is worth untangling, because the two halves of this reform get quoted at homeowners interchangeably and only one of them is relevant.

Approved Documents are statutory guidance to the Building Regulations 2010 for England. Compliance is judged against the Requirements in Schedule 1; the Approved Document shows one way of meeting them. Your building control body has the final word on your specific building.

Read the table twice and the shape becomes obvious. Six of those seven rows are about buildings you do not own. One row — the first — is about you, and it is the one that gets the least coverage.

Your three duties as the client

They are not paperwork for its own sake. Each one exists because a specific thing used to go wrong.

1. 01Appoint people you have taken reasonable steps to check are competent. The duty is on the appointment, not on your technical judgement. You are not expected to assess structural calculations. You are expected not to hand your house to someone you never checked.
2. 02Appoint a principal designer and a principal contractor in writing, where more than one contractor is involved. Almost every extension involves more than one contractor. If you do not make the appointments, the duties do not vanish — they land on you by default, which is the outcome the requirement exists to prevent.
3. 03Give the dutyholders the information you already hold about the building. Old drawings, a previous structural report, the party wall award from next door's work, the fact that the rear addition was rebuilt in the nineties. Information you have and they do not is the cheapest risk reduction on the project.
4. 04Take reasonable steps to satisfy yourself the work meets the Building Regulations. This is not a duty to inspect it yourself. It is a duty not to look away — which in practice means keeping the inspection record and asking to see it.

The one that catches people

The written appointment. On a domestic project it is usually a single line in the contract or an email confirming that the contractor is taking the principal contractor role and the architect the principal designer role.

When it is missing, nothing appears to be wrong. The work proceeds, the inspections happen, the extension gets built. The consequence only surfaces if something goes wrong afterwards and somebody asks who was carrying the duty — and by then the answer is you.

Where this meets building control

Dutyholder duties sit alongside building control, not instead of it. Your project still needs the right control route and still gets inspected at the notifiable stages, and those stages close permanently the moment work is covered up.

We wrote the full picture out separately rather than compressing it here:

• The building control explainer — which route your job needs, the inspection stages, and what happens if work was done without approval.
• The Building Regulations reference — every Approved Document figure that comes up on a domestic project, each with the clause it comes from.
• The permitted development rules — because planning permission and building control are separate consents, and having one has never implied the other.

What we do about it

We take the principal contractor role and confirm it in writing before work starts, and where we are designing as well, the principal designer role with it. That is not a favour — it is the appointment the regulations expect the client to make, and making a client chase it is a poor start.

The rest is record-keeping, which we would do anyway. No variation happens without your written approval: every one is priced and dated before a penny is spent on it. The same record that keeps a variation honest is the record that answers "who decided this, and when" if anyone ever asks.

What this does not mean

Three things worth saying plainly, because the Building Safety Act is used to sell things.

It does not make your extension a regulated high-rise. If a supplier or a contractor tells you Gateway 2 approval is needed for your rear extension, they have either misunderstood the legislation or are hoping you have.

It does not mean the levy applies to you. It starts on 1 October 2026 and exempts developments of fewer than 10 units. One home is one unit.

It does not change what the work costs. Appointing a principal contractor is an appointment, not a line item — if it appears as an extra on a quotation, ask what it is buying that the contract does not already require. If you want a figure for the work itself before you speak to anyone, the cost calculator gives a range in a couple of minutes, and a house extension is priced from the same engine whoever carries the duty.

It does not replace your own judgement about who you appoint. The duty is to take reasonable steps. Reasonable steps are: current insurance certificates you have actually seen, a named person who will be on your job, two comparable projects you can look at, and a written method for how variations and inspections get recorded. A competent contractor produces all four in a day. That is the test, and it is the same test whether or not the law had ever used the word dutyholder.

The honest limitation

This is a general explanation of a regime that applies across England, written for a homeowner planning work in London. It is not legal advice on your project, and the Building Safety Regulator's own guidance is the authority on any point where precision matters.

Where a specific figure decides something on your job — a fire resistance period, a foundation depth, a ventilation rate — take it from the reference, which carries the clause, rather than from prose anywhere including here.