info@plansing.co.uk 167-169 Great Portland Street, London United Kingdom +443301339001

London’s Trusted Build-Over Agreement Specialists

    Planning to build over a public sewer?

    Our expert build-to-agreement services handle drawings, applications, and Thames Water approval to keep your project compliant and delay-free. At Plansing, we help homeowners and developers across London secure approvals quickly with expert-led build-to-agreement services. With 10+ years of experience and 50,000+ completed projects, we know exactly how to get it approved without the back and forth.

    Home extension build over agreement construction project in London

    What is a Build Over Agreement?

    A build-over agreement is an official permission from the local water authority (such as Thames Water) allowing you to build over or near a public sewer. If your project affects existing drainage, you must apply for a build-over agreement before starting construction. This is a legal requirement across London and the surrounding boroughs. At Plansing, we manage the entire build-to-suit agreement application process, ensuring full compliance with Thames Water regulations. Whether it’s a new build or a retrospective build over an agreement, we make sure your project avoids damage risks, delays, and costly issues in the future.

    Plansing — Types of Build Over Agreement Services

    Types of Build Over Agreement Services We Provide

    We provide a full range of build-to-agreement services to help homeowners and developers get fast approvals and ensure compliance with water authority regulations. With 10+ years of experience and 50,000+ completed projects, we ensure your project is safe, compliant, and stress-free.

    01

    Home Extension Build Over Agreements

    We prepare and manage build-over agreement applications for home extensions, ensuring your sewer connections are checked and approved before construction begins.

    02

    Loft Conversion Build Over Agreements

    Converting your loft near a public sewer? We handle the drainage assessment and Thames Water approval so your project stays fully compliant.

    03

    Garage Conversion Build Over Agreements

    Turning your garage into living space can affect nearby drainage. We manage the full build-over agreement process for a smooth, quick approval.

    04

    Conservatory Build Over Agreements

    Adding a conservatory close to a sewer line requires official permission. We prepare the drawings and secure approval on your behalf.

    05

    Drainage & Sewer Assessment Services

    Our engineers assess existing drainage and sewer routes to determine whether your project requires a build-over agreement.

    06

    Structural Design for Build-Over Projects

    We produce accurate structural drawings that meet water authority standards, giving your application the best chance of fast approval.

    07

    Thames Water Build Over Agreement Support

    We liaise directly with Thames Water, managing correspondence and documentation until your agreement is fully approved.

    08

    Renovation & Property Alteration Agreements

    Renovating near a public sewer? We ensure your alterations comply with build-over agreement regulations from start to finish.

    Plansing — Our Simple 4-Step Process

    Our Simple 4-Step Process

    01

    Consultation

    Tell us about your project.

    02

    Assessment

    We confirm if you need a sewer build-over agreement.

    03

    Drawings & Application

    We prepare the Thames Water build-over agreement drawings and submit.

    04

    Approval

    We manage everything until approval is secured.

    BUILD OVER AGREEMENT

    Ready to Get Started?

    Don't risk delays, rejection, or costly mistakes. With Plansing, you get expert support, accurate drawings, and a smooth approval process from start to finish.

    Apply for your build over agreement now
    Hire a specialist and get it approved faster
    Speak to an expert today
    Hire a Build-Over Agreement Consultant
    Hire a build-to-agreement consultant you can trust!

    Why Choose Us

    Complete Build Over Agreement Support You Can Trust

    Expert Structural & Compliance Guidance

    We are a trusted build-over-agreement specialist in London, providing expert structural and drainage compliance support to ensure your project meets all water authority requirements.

    Professional Assessment & Honest Advice

    We offer clear, practical advice customised to your property and project type, helping you understand risks, requirements, and approval steps before construction begins.

    Stress-Free Approval Process

    From drainage checks to technical drawings and full application support, we manage the entire build-over agreement process so you can move forward without delays or confusion.

    Protect Your Property & Ensure Full Compliance

    Our detailed inspections and engineered solutions safeguard your property structure while ensuring full compliance with regulations, helping you avoid disputes and approval issues.

    Got Questions?

    Frequently Asked Questions

    How do I apply for a build-over agreement?

    You need to submit a build-over agreement application with drawings and drainage details to your water authority. We handle the full process for you.

    Can I build without a build-over agreement?

    No. Building without a building-over-sewer agreement can result in legal action or forced removal.

    What is a retrospective build over agreement?

    Its approval is requested after construction is already completed. It's more complex and not always guaranteed.

    Do I need drawings for a build-over agreement?

    Yes. Accurate build-over agreement drawings are essential for approval.

    How much does a build over agreement cost?

    Costs vary depending on the project and authority. Contact us for a quick quote.

    Can I find a build-to-agreement service near me?

    Yes, Plansing provides expert services across all London boroughs.