Adding An Extension: Do You Need a Party Wall Agreement?

If you’re considering adding an extension to your home, you’ve probably thought about your neighbour. Throughout the whole process, you’ll need to consider them due to construction noise, and most importantly, the Party Wall Agreement.

The Party Wall etc. Act 1996 must be abided by if you need to perform any construction or maintenance on a party wall. Failing to get your neighbour(s) to sign off legal paperwork stating that the extension is allowed can result in legal repercussions.

To avoid this, before you undergo any work on a party wall, I suggest you become knowledgeable on the below.

Why you need a Party Wall Agreement when adding an extension

When we think about a Party Wall Agreement and homeowners wanting to add an extension, we vison urban areas. Almost all homes located in a city (such as London) will require you to need a Party Wall Agreement to undergo an extension. If you’re unsure whether or not your extension will need a Party Wall Agreement, contact us.

Nonetheless, here are three primary reasons why you need an official Party Wall Agreement when adding an extension.

Setting The Requirements

Firstly, the main reason why you need a Party Wall Agreement is to provide your neighbours with adequate information on how the construction will be carried out. For example, this will include an overview of what construction you’re doing (adding an extension), how it may affect your neighbour regarding the party wall, and clauses you must abide by.

The clauses are particularly important, as a Party Wall Surveyor will suggest what you can and cannot use on the party wall to ensure structural strength doesn’t decay. For example, they may say you cannot use percussive power tools on the wall as it’ll generate vibration, causing it to crack, etc.

Schedule of Condition Report

Another reason you need a Party Wall Agreement when adding an extension is the Schedule of Condition Report. This report is mandatory with all Party Wall Agreements, and it’s used to protect you and the neighbour.

Please note – When getting this report, it’s recommended to get an RICS rated party wall surveyor to guarantee they meet ethical and professional results. If you’re unsure where to find one, don’t hesitate to get in touch with us.

The report itself will have a written statement of the property’s condition and various photographs to back the findings. Suppose anything was to become damaged during the construction process. In that case, the owner of the Party Wall Agreement (the person adding an extension) will be liable for any damages done to the party wall.

Project Drawings

Lastly, another significant reason you need a Party Wall Agreement for this type of work is so the party wall surveyors can assess the architectural and structural drawings to ensure the building owner is carrying out works in accordance with the act. Here, they’re able to evaluate the drawings to see if anyt adjoining owners require notices to be served upon them. 

For example, when adding an extension, you may not be building right up to the boundary however your extension is still within 3m of a neighbours building therefore you would need to serve notice(s) in accordance with section 6 of the Party Wall Act

As you can see, whether you live in a rural area or a big city like London, you need a Party Wall Agreement to cover yourself from any legal issues. Although that’s great, it also reduces the chances of your project causing a breakdown in relations with your neighbours as you’re considering the implications your build may have on them before undergoing any work.

Do You Need a Party Wall Agreement When Adding An Extension?

I’ve mentioned above that the probability of needing a Party Wall Agreement to add an extension in London is extremely high. But what are the circumstances that you don’t need one?

Because cities like London are so highly congested, it’s scarce you won’t need a Party Wall Agreement when adding an extension. However, if you’re lucky enough to have a vast amount of land on your property, you might not need to get an official agreement.

The main reason why you wouldn’t need one is that you’re not altering or changing the party wall or any party-related boundaries. However, you may still need to get an agreement in some cases, even if you don’t physically perform construction on the wall. Typically, when you perform excavation close to the party wall (around 3 meters), you’ll need a Party Wall Agreement. This is because it may affect the overall structural integrity of the wall / adjoining owners property.

However, if you’re unsure whether you need a Party Wall Agreement or not, always double-check. 

If you live in London or surrounding areas, feel free to contact us. From here, we provide a package depending on your party wall needs. We’re able to send out a fully certified Party Wall Surveyor, to carry out a schedule of condition report, and even provide the final awards to ensure you’re complying with the Party Wall etc. Act 1996.

London Office:

4th Floor, Silverstream House,

45 Fitzroy Street




0800 464 7131

Essex Office:

282 Leigh Road

Leigh on Sea



0800 464 7131