Basements are becoming a sought-after way to maximise living space, especially in cities where property is scarce and costly. Whether you’re looking to convert an existing basement or build a new one, there are several considerations — both for the homeowner and the neighbours.
Here’s how the Party Wall etc. Act 1996 comes into play when planning basement construction, and what steps you need to take to avoid costly issues down the line.
Why Are Basements So Popular?
In cities and towns, basement developments offer a unique solution to space limitations. Homeowners often use basements to create extra rooms like play areas, gyms, swimming pools, or even supplementary accommodation. But there are also challenges involved, especially when excavation work is required beneath existing properties.
If you’re a neighbour, the thought of large-scale construction next door can be unsettling. You’ll want to be aware of how it may affect your property, even if it’s just the noise, dust, or general disruption. As a Building Owner planning the basement, it’s essential to understand how the works could affect the surrounding properties.
The Party Wall Act 1996 and Basement Work
The Party Wall etc. Act 1996 protects Adjoining Owners when work is carried out that might affect their property. Section 6 of the Act specifically addresses the issue of excavations near a neighbour’s property that could undermine its foundations. If your project involves basement works, you need to make sure you serve the appropriate notices under this Act.
Understanding the Risks of Basement Excavation
When constructing a basement, the process involves digging below the foundation of the building, which can weaken the surrounding soil and structures. If the excavation is not properly planned, it can lead to serious issues, like subsidence, cracking walls, or tilting foundations. A structural engineer should design a solid solution, with underpinning potentially required to reinforce foundations.
The Importance of Professional Input
Structural engineers play a critical role in basement projects, as they help design the foundation reinforcements and underpinning that are required for stability. In older buildings, additional issues such as ‘corbels’ (protruding bricks at foundation level) may need trimming to allow for the new foundation works. These special foundation issues must be properly addressed, especially if they involve party walls, requiring notices to be served on the neighbouring owners.
Special Foundations and Party Wall Notices
Sometimes, complex solutions like cantilevered or overhanging foundations are used to avoid overloading an existing foundation. These methods — which are considered ‘special foundations’ — will trigger the need to serve Party Wall notices under the Act.
If your basement development involves retaining walls or reinforced concrete structures, these too will need to comply with Party Wall procedures. Even small changes, like lowering foundations, can have an impact on the shared party wall and require formal notification.
Waterproofing and Damp Concerns
One of the biggest challenges in basement construction is managing water ingress. Modern basements, particularly those dug deeper than older Victorian ones, can face issues with water pressure and dampness. Without proper waterproofing (or ‘tanking’), these spaces can quickly become unusable. Testing the subsoil and implementing effective damp-proofing measures are crucial steps to prevent water from damaging the new structure.
Monitoring Movement During Excavation
During excavation, it’s important to monitor any movement in the building and neighbouring properties. If not carefully managed, excavation can lead to horizontal forces that could destabilise the surrounding structures. Steel pins, dynamic monitoring systems, and regular site inspections can help track any changes and mitigate risks.
The Role of the Party Wall Surveyor
Given the complexity and potential risks involved in basement development, it is always recommended to appoint a Party Wall Surveyor. Their role is to ensure that the work complies with the Party Wall etc. Act 1996 and to protect the interests of both the Building Owner and the Adjoining Owner. The surveyor will mediate between the parties, help with notices, and ensure the safety and stability of the work.
Why Hire a Party Wall Surveyor?
A Party Wall Surveyor helps navigate the technicalities of the Act and ensures the project is adequately planned and engineered. They’ll also set out any agreed working hours, noise management, and potential disruptions. Before signing off any final Agreement, the surveyor will ensure that the project will not endanger neighbouring properties and that all necessary consents are in place.
Final Steps
Before you commence any basement development, make sure all your statutory consents and Party Wall notices are in place. Building Control, Planning permission, and Listed Building Consent may be required, in addition to the necessary Party Wall notices. Proper planning and professional input from a structural engineer and Party Wall Surveyor will ensure your basement project goes smoothly.
If you’re planning basement works or need advice on how to navigate the Party Wall Act 1996, get in touch with our experts today at team@simplesurvey.co.uk. We’ll guide you through the process and ensure your project complies with the law while protecting your property rights.