You have sent the notices, spoken to the neighbours and started organising the builders. Then something changes.
Perhaps the structural engineer recommends a different foundation. Perhaps you decide to keep the chimney breast after all. Or the builder opens up part of the house and discovers that the wall is not quite where the drawings suggested.
Changes like these can happen during a renovation. The important question is whether your party wall paperwork still covers the work you now intend to carry out.
For London homeowners, especially those extending terraced houses or converting lofts, it is worth checking before the revised work begins. An earlier notice or Party Wall Award should not be treated as permission for every later version of the project.
First, work out what has actually changed
A new drawing does not necessarily mean you need to restart the party wall process.
Moving a kitchen cupboard, choosing different flooring or changing an internal finish might have no effect on the work covered by the Party Wall etc. Act 1996. A revised foundation depth or a new beam bearing into a shared wall is a different matter.
The useful question is: does this change alter the work affecting the neighbouring property, shared structure or boundary?
Your surveyor will need to compare the original proposal with the revised design. Simply sending the latest drawings without explaining the changes can make that comparison harder than it needs to be.
Ask your architect or engineer to identify the revisions clearly. A short explanation alongside marked-up drawings can save several rounds of emails.
What if your neighbour has already consented?
A neighbour’s written consent relates to the work described in the notice. You should not assume it automatically extends to additional or substantially different work.
Imagine you originally proposed a rear extension with foundations shown at a particular depth. Your neighbour consented on that basis. The engineer later specifies deeper excavation beside their house.
The extension may look exactly the same above ground, but the excavation proposal has changed. That needs checking.
Depending on the circumstances, the revised work may require further information, fresh consent or a new notice. If a dispute arises, the surveyor appointment and award procedure may become necessary.
Avoid relying on a casual conversation such as, “They said they were fine with the extension.” It helps to have a clear written record of the revised proposal and the appropriate response.
Our guide to the difference between a Party Wall Notice and a Party Wall Award explains why these documents serve different purposes.
What if a Party Wall Award is already in place?
Start by checking the award and the drawings it refers to.
An award normally deals with specified work and sets out the relevant conditions for carrying it out. If the construction drawings have since changed, the contractor needs to know which details remain covered and which need further consideration.
Section 7(5) of the Act addresses departures from agreed or determined plans. Changes need to be agreed through the appropriate parties or surveyors, or resolved through the Act’s dispute procedure where necessary.
That does not mean every revision requires a completely new award. Equally, it does not mean a builder can substitute a different detail because it seems more convenient on site.
Ask the surveyor to confirm the correct route. Depending on the nature and scope of the change, this could involve recording an agreed revision, a further award or fresh notices for additional work.
Get the position clarified before carrying out the affected part of the project.
Small changes can matter more than they appear
Homeowners understandably judge changes by what they can see. A slightly different steel beam or foundation detail might seem less significant than replacing an entire kitchen.
For party wall purposes, the structural detail can be the more important change.
Examples worth referring back to your surveyor include:
- Moving or adding a beam bearing into the party wall.
- Changing the depth or position of excavation near a neighbouring building.
- Introducing underpinning that was not included in the original proposal.
- Altering the height or extent of work to a shared wall.
- Adding chimney breast removal to an existing renovation.
- Changing temporary support arrangements affecting the adjoining structure.
These changes do not all follow the same procedure. Their effect depends on the original documents, the revised work and the neighbouring property.
If your revision involves structural steel, our article on party wall agreements for installing steel beams provides useful background.
Planning approval does not settle the party wall position
Your architect may need to discuss a revised design with the council. Building control may also need updated structural information.
Those checks are separate from the party wall process.
A revised planning approval does not automatically update an existing notice, your neighbour’s consent or a Party Wall Award. Likewise, agreement under the Party Wall Act does not replace any planning or building regulations requirements.
Keep everyone working from the same information: architect, engineer, contractor and party wall surveyor. Problems become harder to resolve when each person holds a different version of the drawings.
What to send your surveyor
You do not need to write a lengthy report. Send a clear package containing:
- The original notice and any written neighbour responses.
- The Party Wall Award, if one has been served.
- The drawings referred to in those documents.
- The revised drawings, with dates and revision numbers.
- A brief explanation of what changed and why.
- Your intended date for carrying out the affected work.
If construction has already started, explain what has been completed. Photographs may help the surveyor understand the current situation, although an inspection may also be needed.
Be specific. “The foundations have changed” is less useful than an explanation showing the previous and proposed depths and their positions relative to the adjoining building.
Can other building work continue?
That depends on the project.
A revision affecting one structural detail does not necessarily prevent every unrelated job from continuing. However, the contractor should not proceed with the changed notifiable work while assuming the paperwork can be sorted out afterwards.
Ask your surveyor and design team to identify the affected operations. This gives the builder a clearer basis for planning the programme.
For example, some internal finishing work may be unrelated to a revised excavation proposal. Temporary support or structural demolition could be closely connected to it. The distinction needs to