Needing drain repairs can make a homeowner’s heart sink. The expense and mess of repairing pipes buried beneath the ground, maybe even under the home itself, is a scary prospect. Drains pass under tarmac, concrete and even walls. Replacing drainage pipes can quickly turn into a major piece of work.
However, happily, there is often a cheaper, easier alternative: drain lining. Simply put, drain lining is a less disruptive way to repair a damaged drain. Rather like keyhole surgery to repair a damaged blood vessel, drain lining can be carried out through a much smaller hole than that needed by a full-scale drain pipe replacement.
A Pipe Within a Pipe
As you may have guessed, drain lining involves lining the drain pipe. A lining, made of polymer, is passed down inside the pipe, then bonded to the existing drain. The end result is effectively a pipe within a pipe. The National Association of drainage contractors has an explanatory video here: http://www.nadc.org.uk/drain-lining-c512.html.
This does of course reduce the internal width of the pipe, making it slightly narrower, but in many cases this is a minor issue compared to the inconvenience of digging out the existing drains and replacing them.
How Does Drain Lining Work?
Firstly, a drain lining company will investigate the damage to the pipework. To assess the condition of the drain, the inside of the drain pipe will be cleaned out with a pressure washer. Next, a camera with a torch on a long cable will be pushed into the drain, letting the drainage engineers examine every inch of the drain. If drain lining will solve your drain problem, they will gently feed the liner into the drain. The liner is moved carefully into position until the damaged area of the drain is fully covered. Once the liner is placed correctly, an airbag inside the liner is inflated, pressing the liner against the inside of the damaged drain. The liner will then harden, creating an inner pipe within the original drain. Once the liner has hardened, the air bag is removed.
A good drain lining company, such as https://www.wilkinson-env.co.uk/sewer-repairs-drain-lining-concrete-cutting/, will then check once more with the camera to ensure the drain lining has worked as expected.
Where drain damage is localised to a small area, drain lining can be applied as a patch.