Drain Lining Cost

Other factors affecting the cost of a drain liner

Normally, an inspection would be carried out first using a CCTV camera to assess the extent of the problem. A national average for this ranges from £90 to around £350. However, there are other factors which can affect the final bill and these include:-

• The site and vehicle access – this refers to the number of access points or manholes and the number of connections within the drains
• The number of lateral cuts – once a drain is relined, it can often block what is called lateral cuts, these are the intersections with other pipes and they have to be cut out to allow the drain to function properly. The more lateral cuts required, the longer it takes
• Existing pipe condition – high-pressure water jetting may be needed to clean the pipe and break up debris before the liner is inserted
• Location – drain services are almost always more expensive in London and the South East

What is drain lining?

Drain lining is a non-invasive way to repair damaged drains. Rather than digging down and exposing the drain, access is gained at ground level and all repairs are carried out within the drain using just a small access hole.

Drain lining involves the lining of a drain with a polymer sleeve which then bonds to the inside of the pipe – it is like building an extra pipe within the existing drain pipe. The liner is gently fed into the prepared drain and it moves along slowly covering the interior surface including the damaged portion. Once in place, an airbag within the liner is inflated and pushes the soft liner out towards the surface of the pipe until it fits the exact diameter.

The liner will need to cure and harden to create this second pipe within a pipe. The inflated air balloon is then deflated and removed. Finally, the robotic camera either on a drain crawler or access rods is fed through the drain to inspect the work. If necessary, holes are cut in the liner to enable it to connect to any adjoining pipes and then the job is finished and the drain ready for use once again.

How is the drain assessed and the problem located?

Drain lining is not suitable for all drain problems so, in order to assess fully the extent of the problem, the internal surface of the drain is jet washed and then a small CCTV camera is sent along it positioned on the end of flexible access rods to closely inspect the drain and identify the problem. For example, it could be the case for external taps that weathering has caused a problem with water flow. Read our page on outside tap fitting costs for more information.

Are there any disadvantages to drain lining?

The area through which fluid can move will become slightly reduced but this is generally considered preferable to the alternative of extensive and expensive groundworks to expose the defective pipe. And relining is not possible in all situations. Incorrect installation can mean that tree roots can still grow back and penetrate between the liner and the original pipe so it is important to use experience and reputable drain engineers to undertake this work.

What is patch lining?

Sometimes, a full drain line is not required or justified and there is an alternative called ‘patch lining’. Patch lining allows the drain engineer to just treat one spot which is reasonably confined in both location and size. Patch lining is similar to full drain lining but just uses a single piece of lining material rather than a whole cylinder. The patch is moved gently down the drain until it arrives at the point which has been identified as the problem area. The air balloon is inflated and pushes the patch into contact with the damaged pipe. The patch then cures, glueing itself rigidly to the inner surface of the pipe and repairs the damage.

Drain lining has revolutionised drain repair, requiring little or no excavation and eliminating the need for costly restoration afterwards. It is ideal for hard to access areas where excavation is challenging and it creates minimal disruption. It is a quick, simple solution which is also able to negotiate bends in the pipe without wrinkling or crinkling and off-set joints. Lots of different types of pipe material are suitable for drain liners which have a much longer guarantee than many new PVC pipes. Most drain lining can be completed in one day once the initial camera survey has taken place and the cost of drain lining is usually far less than the alternative excavation work and pipe replacement.

Drain lining was originally a system devised for large diameter main sewers but the technology has been adapted for use in domestic situations and the advent of modern materials makes this a cost-effective and non-invasive solution for many drain repairs.

When looking for a contractor, try to find someone who clearly meets the standards set by industry regulators. If the drain lining is installed to WIS – Water Industry Specification – standards the life of the liner is fifty years. A reputable contractor should be able to offer a long guarantee and warranties which are a minimum of five years in length.

See more information from the government on reporting blocked drains, along with guidance from Citizens Advice on who is responsible for drains and sewers.