Why Drain Surveys Are Essential Before Building a Garden Room or Annex
Garden rooms and annexes have become incredibly popular across Derby and Derbyshire, offering extra living space without the need for a full home extension. Whether you are setting up a home office, a gym, a guest space, or a hobby room, these structures still require careful planning to ensure you do not build over essential underground services.
One of the most overlooked elements is the property’s drainage system. Many homeowners assume a garden building will not affect the drains, only to discover late in the project that their structure sits above a public sewer or that their drainage layout is not compliant with planning requirements.
A professional CCTV drain survey helps you understand exactly what is beneath your garden before construction begins. This protects your investment, keeps your project fully compliant, and prevents expensive mistakes.
Why Garden Buildings Need Drain Checks
Even small garden rooms can interfere with drainage routes. Common issues include:
Public sewers running beneath the proposed garden room
Private drains located close to the foundations
Shared drainage between neighbouring properties
Incorrect historic mapping of drainage systems
Old clay or pitch fibre drains weakened by age or roots
If your building sits on top of a public sewer or obstructs access to a drain, you may not receive approval from Severn Trent Water, and your builder may be forced to halt work.
What Is a Drain Survey for Garden Buildings?
A Garden Room Drain Survey is a specialist CCTV inspection designed to map and assess the drainage systems beneath your construction area. Using HD camera technology, our engineers inspect your drains and provide a report confirming:
The exact location and depth of drains
The condition of each drainage line
Whether the proposed structure affects access to the drains
Any cracks, blockages, or defects requiring attention
Whether Severn Trent approval is likely to be required
This survey gives both you and your builder confidence that your project is safe and compliant.
The Importance of Drain Mapping for Garden Rooms
Many older drainage systems in Derbyshire were never properly documented. As a result, homeowners often have no idea where their drains run. During planning, this can lead to serious issues such as:
Misplaced foundations over a public sewer
Conflict with neighbour’s drainage systems
Building control requesting additional inspections
Forced redesigns midway through construction
Accurate drain mapping prevents these problems and ensures your garden room is positioned safely.
Common Drainage Problems Found Beneath Garden Plots
Across Derby, Hilton, Burton, and surrounding villages, we often discover:
Cracked clay pipes vulnerable to collapse
Tree root intrusion beneath garden boundaries
Collapsed drains caused by age or ground movement
Unmapped or shared drains running across gardens
Redundant pipes that were never properly sealed
When planning a garden building, these issues can affect foundation depth, structural safety, and long term drainage performance.
How a Drain Survey Protects Your Project
A professional survey from Derby Drain Surveys helps you avoid:
Unplanned excavation
Disputes with neighbours over shared drains
Delays caused by planning refusals
Safety issues due to damaged pipework
Expensive redesigns once construction begins
Having the correct drainage information from the start helps your builder plan effectively and keeps your project stress free.
Professional Treatments for Drain Issues Beneath Garden Rooms
If we find defects during the survey, we offer a range of treatments to keep your project moving:
Pipe relining to repair damaged pipes without digging
Root cutting to remove intrusive tree growth
Jet washing to improve flow and remove debris
Excavation and replacement for severe damage
Sealing redundant drainage runs for safety and compliance
These treatments ensure your drains remain safe and functional for years to come.
Why Choose Derby Drain Surveys
With over 20 years of drainage and construction experience, we provide reliable, accurate surveys for homeowners planning garden rooms and annexes across Derbyshire. Our reports are detailed, compliant, and accepted by planning departments and Severn Trent Water.
We offer:
HD CCTV inspections
Full mapping and written reporting
Fast turnaround for urgent projects
Cost effective treatments
Honest, expert guidance from local specialists
You can start your project with complete confidence that your drains are safe, compliant, and ready for construction.
Build With Confidence
Do not risk planning delays or structural issues by guessing what is beneath your garden. A drain survey is the easiest way to protect your investment and keep your garden building project on track.
Click here to book your Build Over Drain Survey or learn more about our professional CCTV drain inspections for home extensions in Derbyshire.
📍 Based in Derby. Serving Derbyshire, Hilton, Burton, Etwall, and the surrounding Midlands towns.
