What is the Party Wall Act 3m rule and is it something you should be worried about? This is what the experts say

If you are planning on starting some building work and have neighbours, you may need to know what the Party Wall Act 3m rule is. Especially given the fact that if you ignore it and you could end up in some rather hot water.

While party walls can often be a bone of contention between owners of neighbouring properties, this is most certainly not always the case. Usually, it is just a matter of good communication and a willingness to adhere to the rules surrounding them.

Here, we take a look at the Party Wall Act 3m rule, explaining what it is, why you might need to know about it and how to ensure you are carrying out your home project in accordance with it.

What is the Party Wall Act 3m rule?

Even if your building work doesn't require planning permission, you may still need to pay attention to the Party Wall Act 3m rule.

'The Party Wall Act 3m rule is a provision under the Party Wall etc. Act 1996 that applies when excavation work is planned near a neighbouring property,' explains professional planning consultant Simon Rix, of Planix.uk.

'If you intend to dig within three metres of an adjoining building and the excavation will go deeper than the neighbour’s foundations, you are legally required to serve a Party Wall Notice,' continues Simon.

It is worth noting that this is not a rule that applies throughout the UK.

'The Party Wall Act only applies to houses in England and Wales,' points out Paula Higgins, Chief Executive of HomeOwners Alliance. 'It doesn't apply in Scotland or Northern Ireland.'

Simon Rix

Simon Rix is a professional planning consultant, who began his career working in local government in the 1990s. He was a council officer and later an elected councillor, so he knows how the planning system works from both sides. He went on to set up Planix.UK Planning Consultants Ltd; a consultancy company that advises self builders, home extenders and those taking on small to medium-sized building projects on planning permission.

Paula Higgins

After spending 15 years reforming housing policy in government, enough was enough. Homeowners needed a voice and HomeOwners Alliance was born

What does a homeowner need to do?

Whether you are building an extension, constructing a garden building or even a structure such as a wall, and the work will fall within three metres of your neighbours wall, you are going to need to take action before ploughing ahead.

'If you plan to excavate within 3 metres of a building or structure on your neighbour's land, such as a garden wall or a shared party fence wall, and the excavation will be deeper than the bottom of the foundation of the adjoining structure, you must serve a Section 6 – ‘Excavation and Construction’ Notice under the Party Wall etc. Act 1996,' explains party wall surveyor Richard Johnson of partywall.expert.

So, exactly how do you do this? Paul Higgins explains.

'The Party Wall Act's 3 Metre Rule requires property owners to serve a formal notice to their adjoining neighbours,' she begins. 'This notice must be provided in writing at least one month before the planned work commences. This gives neighbours the opportunity to consent to or dispute the proposed works.

'The purpose of this rule is to prevent potential damage to neighbouring properties due to construction work.'

'A Section 6 Notice must include detailed plans and sections showing the site, the depth of any proposed excavation, and the location of any new structures,' adds Richard Johnson.

Do you have to submit a notice?

If you are wondering is it illegal to ignore the Party Wall Act or thinking you can get away without serving your affected neighbours with notice of your intended works, then think again – failure to do so could mean you are breaking the law.

'The adjoining owner could apply for an interim injunction at court to stop you proceeding with notifiable works,' warns Richard Johnson. 'You would have to comply with the injunction and stop work. Failing to comply with an injunction could result in a fine or even committal to prison.'

What happens if the neighbour doesn't give consent?

Your extension ideas are in place, the work has been planned, the notice has been served to the owners of the affected property and everything seems to be going to plan. But then, you get a response you weren't expecting – your neighbours refuse to agree with the work you intended to carry out. What then?

'By serving a Party Wall Notice, this gives your neighbour the opportunity to review the plans and either consent or dissent,' explains Simon Rix. 'If they dissent, a Party Wall Agreement must be put in place, often involving the appointment of a party wall surveyor.'

'In this case, both homeowner and neighbour can appoint one agreed surveyor, usually within ten days, who can act impartially for both,' picks up Paula Higgins. 'The agreed party wall surveyor should be independent and not the same surveyor the homeowner might be using for their own works. Otherwise their neighbour is unlikely to view the surveyor as neutral.'

What's the Party Wall Act 6m rule? 

There are some instances where work that is being carried out further than 3m from a neighbour's wall might require you to serve a Party Wall Notice.

'The Party Wall etc. Act 1996 specifies two key distances,' says Richard Johnson. 'Within 3 metres of the adjoining owner's building or structure and between 3 to 6 metres away, where deeper excavations like those for basement conversions or piling may be involved.

'Most domestic work falls within the 3-metre rule.' continues Richard. 'However, deeper excavations between 3 and 6 metres can also trigger the requirement to serve notice.

'Early consultation with an experienced party wall surveyor is crucial to determine whether your project falls under the 3-metre or 6-metre rule of Section 6 of the Party Wall etc. Act 1996 and to assess the need for safeguarding your neighbour’s foundation,' adds Richard.

Where to go for help

If you are in any way unsure whether or not your proposed works will mean you need to serve a Party Wall Notice to your neighbours, it is well worth consulting with a party wall surveyor.

FAQs

How do I know how deep my neighbour's foundations are?

The Party Wall Act 3m rule applies when you are carrying out any excavation work, within three metres of a neighbouring property, and will be digging deeper than the foundations of that property – but how do you know how deep they are?

'If you live in semi-detached or terrace, the adjoining owners foundations are likely to be the same depth as your foundations,' explains Richard Johnson. 'You can therefore excavate a trial hole on your land. However, the older the property generally the shallower the foundations. So, on a pre-war building you should assume a foundation depth of 400mm and post war, 600mm. Typically modern foundations will be to a depth of at least 900mm.'

There are lots of home improvements you can do without planning permission, but take care. They will usually still require building regulations approval and, in some cases, the Party Wall Act will apply too.