Whether you're installing a completely new drainage network or extending an existing system, understanding how to connect underground drainage pipes properly helps ensure a safe and durable installation.
In this guide, we'll explain how underground drainage systems work, the materials you'll need, how to prepare your installation and the correct process for joining underground drainage pipes and fittings. Keep reading to learn more, or to speak directly to an expert, call us now on 01420 555600.
How Underground Drainage Systems Work
Underground drainage systems transport wastewater safely away from buildings through a network of pipes, fittings and inspection chambers. The system relies on gravity, meaning every section of pipe must be installed with the correct fall to allow water to flow efficiently. Secure pipe connections are equally important, helping prevent leaks while maintaining the integrity of the drainage system.
Materials Required
Underground Drainage Pipes
Underground drainage pipes form the main network that carries wastewater away from a property. In the UK, they're typically manufactured from durable PVC-U and are commonly available in 110mm and 160mm diameters for domestic and commercial applications. Choosing the correct pipe size depends on the drainage design and expected flow rates.
Couplers and Connectors
Couplers and connectors join sections of underground drainage pipe together while creating a watertight seal. The type of connector you need will depend on the installation. You may use straight couplers, repair couplers or flexible connectors for joining different pipe materials or accommodating slight movement. View our range of underground connectors.
Bends, Junctions and Adaptors
Drainage systems rarely run in a straight line. Bends allow changes in direction, junctions create branch connections and adaptors connect different pipe sizes or materials. Selecting the correct fitting helps maintain flow and simplifies installation.
Lubricant, Measuring Tools and Cutting Equipment
A quality pipe lubricant helps fittings slide together without damaging seals, while tape measures and marking tools ensure accurate cuts. Pipe cutters or fine-toothed saws produce clean, square pipe ends, helping create more reliable joints.
Preparing to Connect Underground Drainage Pipes
Planning the Pipe Layout
Before beginning installation, carefully plan the route of your drainage system. Identify the locations of inspection chambers and discharge points while keeping pipe runs as direct as possible to maintain efficient flow.
Measuring and Cutting Pipes
Measure each pipe section accurately before cutting. Pipes should be cut square, with any burrs removed from the cut edge to help protect sealing rings and ensure a secure connection.
Check Pipe Gradients and Falls
Gradients allow wastewater to flow efficiently through the drainage system. Falls that are too steep or too shallow can lead to drainage problems, so it’s important to check the gradients are correct before connecting networks.
Inspecting Seals and Fittings
Before assembly, check all seals and fittings for damage or contamination. Clean sealing surfaces and ensure that rubber seals are correctly seated before joining components together.
Process of Connecting Underground Drainage Pipes
The basic process for connecting underground drainage pipes typically involves the following steps:
- Plan the installation by confirming the drainage layout and the required pipe sizes and fittings
- Measure and cut each pipe accurately, ensuring clean, square ends
- Deburr the pipe ends to protect seals during installation
- Apply pipe lubricant to the pipe end and rubber seal where required
- Push the pipe fully into the socket, then withdraw slightly, if recommended by the manufacturer, to allow for expansion
- Connect junctions and adaptors where required, ensuring correct orientation
- Check gradients throughout the installation before backfilling
- Inspect all joints to confirm they're fully engaged and correctly aligned
- Test the system, where appropriate, before completing the installation
Connecting Different Types of Drainage Fittings
Joining Straight Lengths With Couplers
Straight couplers provide a simple way to join two sections of underground drainage pipe. Once the pipe ends have been prepared and lubricated, they're inserted into the coupler until the joint is fully engaged, creating a watertight connection.
Installing Bends
Bends are used wherever the drainage system changes direction. Selecting the correct bend angle helps maintain good flow within the pipework.
Connecting Junctions and Branches
Junction fittings allow additional drainage runs to connect to the main pipeline. Care should be taken to position branch connections correctly to maintain smooth wastewater flow through the system.
Linking to Inspection Chambers
Inspection chambers provide access for future inspection and maintenance while allowing changes in direction or pipe connections. Pipework should align correctly with chamber inlets and outlets to maintain efficient drainage. Browse our range of inspection chamber bases and risers.
Connecting to Existing Drainage Systems
When extending an existing drainage system, it's important to consider compatibility between the existing and new pipework. Flexible connectors or suitable adaptors may be required when joining different pipe materials or diameters.
Checks After Connecting the Drainage Pipes
Before completing your installation, make sure to:
- Check every joint is fully engaged and correctly aligned
- Confirm seals haven't been displaced or damaged
- Verify the correct pipe gradients are maintained throughout your system
- Ensure all fittings are installed in the correct orientation
- Check inspection chambers and branch connections align correctly
- Test the system for leaks
- Confirm pipes are properly supported before backfilling
- Remove any debris from inside the pipework
Speak to Drainfast for Underground Drainage Help
Whether you're installing a new drainage system or extending an existing network, Drainfast supplies all the parts you need to get the job done. From underground drainage pipes and fittings to inspection chambers and flexible connectors, our extensive product selection is backed by expert advice and fast nationwide delivery. Browse our underground drainage range online and order before 5 pm today for next-day delivery within our next-day delivery radius.
Call us now on 01420 555600, email us at [email protected] or fill out our contact form. For larger projects, try our free material take off service.
