Party Walls and Neighbourly Matters: A Guide for Commercial Developers and Investors

Posted by Colliers on 13th January 2026 -

In commercial development, managing third-party risk is essential for protecting your programme, budget and reputation, not just from a planning and technical perspective. One area that’s often overlooked until it's too late is party wall and neighbourly matters.

These issues are a fundamental part of development risk management, particularly on urban or constrained sites. Whether you're refurbishing a commercial asset, undertaking a vertical extension, or delivering a ground-up scheme, addressing party wall and neighbourly matters early is critical.

What are party walls and neighbourly matters?

Party walls are quite simply walls shared by two or more properties. To manage disputes and clarify responsibilities, the Party Wall etc. Act 1996 sets out a legal framework requiring neighbours to be notified of certain construction works, such as:

• Work on or near a shared wall or structure
• Excavation close to neighbouring foundations
• Changes affecting a boundary or party fence wall

The Act is designed to protect both the building owner (you) and adjoining owners (your neighbours) by setting a legal process for notice, response, and if necessary formal dispute resolution via a Party Wall Award.

Neighbourly matters refer to a broad range of issues that can arise between neighbours, such as property rights, boundaries and shared structures. These may include:

• Oversailing agreements (e.g. crane booms or scaffolding licences)
• Access licences
• Rights of light
• Boundary alignment
• Vibration and noise risks
• Monitoring agreements
• Construction-related impact assessments

Why is it important for developers and investors?

• Programme protection - Neighbour disputes or unresolved rights can result in stop notices, legal challenges, or injunctions. These can halt construction and derail your delivery timeline. Early resolution keeps your programme on track.
• Cost certainty - Managing party wall and neighbourly issues proactively reduces the risk of unplanned professional fees, delays, or claims. It also helps identify whether mitigation (e.g. underpinning, scaffold reconfigurations) is needed early - when it's most cost-effective to address.
• Investor confidence - If you’re forward-funding or bringing in joint venture partners, having neighbourly matters under control demonstrates professional risk management. It de-risks the asset and helps secure investment decisions.
  Tenant and stakeholder relationships - In mixed-use or phased developments, neighbourly agreements are essential for maintaining operational continuity for adjoining occupiers, local authorities, or utility providers.
• Legal compliance - If your scheme falls within the scope of the Party Wall etc. Act and you fail to serve notices correctly, works can be legally challenged. More importantly, it can impact insurance, warranties, and dispute resolution if damage arises later.

When should you instruct a party wall or neighbourly matters specialist?

Ideally, from RIBA Stage 2 or 3. Engaging a specialist early allows them to:

• Map constraints across the site boundary
• Serve valid notices on time to avoid delays
• Manage neighbour negotiations professionally and transparently
• Coordinate with your project team on temporary works, design, and logistics
• Advise on access and oversailing strategies tied to craneage and scaffold zones

They’ll also ensure that the developer’s interests are protected in the drafting of legal agreements, surveyor appointments, and monitoring regimes.

Cost implications

Party wall and neighbourly matters are often treated as a minor line in the cost plan, until they aren’t. If not managed correctly, fees for surveyors, legal disputes, or neighbour objections can balloon. By contrast, early involvement typically leads to smoother resolutions, fewer disputes, and far better cost control.

What next?

In commercial development, neighbourly risk is development risk. If you’re building near boundaries, affecting shared walls, or relying on crane and scaffold oversailing, you need to address party wall and neighbourly matters early, professionally, and proactively.

This is about protecting your timeline, de-risking the scheme, and maintaining control. Need early-stage advice or a party wall risk audit on your next site? We’d be happy to assist with upfront strategies, notice planning, and negotiation support, ensuring you move forward with clarity and confidence.