It is not uncommon for neighbouring homeowners to decide to extend at around the same time.
This can be convenient, but it can also create unusual Party Wall and construction issues.
If both projects affect the shared boundary or party structure, coordination becomes particularly important.
Each project should be considered separately
The fact that both neighbours are carrying out works does not automatically remove Party Wall obligations.
Each owner should establish whether their own project requires notices under the Party Wall etc. Act 1996.
Our Party Wall Notice process guidance explains how notices and responses work in practice.
Can the projects share a wall?
Potentially.
Where both owners want extensions along the boundary, there may be practical advantages in agreeing a suitable wall arrangement.
However, design, ownership, structural support and future maintenance should all be considered properly.
Our Section 1 Notice guide is particularly relevant where either owner proposes a wall at the boundary.
Construction sequencing matters
If one extension is built first, it can affect how the second project is constructed.
Issues might include:
- access;
- excavation;
- foundations;
- scaffolding;
- waterproofing;
- roof abutments;
- flashing; and
- the ability to finish external walls.
What if both projects need Party Wall Awards?
The surveyor arrangements will depend on the circumstances and the parties involved.
Where a dispute arises under the Act, a Party Wall Award can regulate how works are carried out.
You can read more in our guide to Party Wall Awards.
Keep clear records
Where substantial works are taking place on both sides, accurate drawings, construction information, photographs and records of the sequence of works can help avoid uncertainty later.
Simple Survey can coordinate the process
If you and your neighbour are both planning works, Simple Survey can review the two schemes and explain how the Party Wall procedures interact.
Visit our Party Wall service page to discuss the projects.