Replacing an old extension can be a great way to improve the layout and performance of a property.
Homeowners sometimes assume that because an extension already exists, rebuilding it cannot create new Party Wall requirements.
That assumption can be risky.
Why can rebuilding change the Party Wall position?
The replacement extension may be:
- larger;
- taller;
- deeper;
- closer to the boundary;
- constructed with deeper foundations; or
- structurally connected to neighbouring walls in a different way.
Any of these changes can affect whether notices are required.
Demolishing an existing wall
If an existing extension incorporates a party wall or party fence wall, demolishing or altering that wall may itself engage the Party Wall Act.
Our guides to what constitutes a Party Wall and Party Fence Walls can help explain the distinction.
New foundations may be deeper
Older extensions sometimes have relatively shallow foundations.
A modern replacement may require deeper foundations to satisfy structural and Building Regulations requirements.
Those foundations can potentially fall within the excavation provisions of the Act where they are close to neighbouring buildings.
What if the neighbour also has an extension?
This is very common in terraced housing.
Your proposed replacement works may sit directly alongside the neighbour’s extension.
Issues can arise around:
- foundation depths;
- exposed walls;
- temporary weatherproofing;
- flashing;
- access;
- drainage; and
- making good.
Where access is genuinely required for work under the Act, our guide to Party Wall Access Rights explains how Section 8 operates.
Do not assume historic consent carries over
An earlier notice or Award relating to the existing extension does not automatically authorise a completely different replacement scheme.
Simple Survey can review replacement extensions
Send us your plans through our Party Wall service page before demolition begins.