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.
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.
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.
WHY CHOOSE US
Our Best Core Values
Online Guidance
You can access expert online guidance through our well-qualified architect. Discuss your expectations related to your space and what you want to make out of it.
Customised Options
Build your home with us; tell us your expectations. Whether it's a new build or an existing one, we provide top-notch contemporary services turning them into reality.
Approval Guaranteed
Our architectural company is renowned for getting planning approvals promptly. From initial documentation to final approval, we handle every step.
Stand Out Designs
Our plans, elevations, and sections are designed from the start to the final stage. We provide built-environment design for living a quality life.
WHY CHOOSE US
Our Best Core Values
Dormer Loft Conversion
Provides extra head height and floor space by extending the roof, making it perfect for bedrooms, bathrooms, or home offices.
Hip to Gable Loft Conversion
The sloping side of the roof is extended to form a vertical wall, making more space available; ideal for semi-detached and terrace houses.
Mansard Loft Conversion
A major roof transformation that maximises internal space, commonly used in built-up areas like London, where extra room is essential.
Velux/Rooflight Conversions
An energy-efficient option to add daylight with roof windows, without altering the existing roof structure.
L-Shaped Loft Conversion
Joins two dormers at right angles to form a large and flexible living area, popular for use on Victorian and Edwardian houses.
Modular Loft Conversion
A prefabricated loft system that is manufactured off-site and assembled on-site, providing a faster and more predictable construction process.
Piggyback Loft Conversion
Typically used on flats or maisonettes, this conversion builds a new structure above the existing roof to create an entirely new living level.
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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.
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Can I build without a build-over agreement?
No. Building without a building-over-sewer agreement can result in legal action or forced removal.
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What is a retrospective build over agreement?
Its approval is requested after construction is already completed. It's more complex and not always guaranteed.
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How much does a build over agreement cost?
Costs vary depending on the project and authority. Contact us for a quick quote.
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Can I find a build-to-agreement service near me?
Yes, Plansing provides expert services across all London boroughs.