Tree root ingress in drains, is where roots – particularly tree roots, but also roots from hedges and shrubs – begin to grow towards, and then into, your drainage pipes. Tree roots in drains is one of the most common causes of blocked drains, and will often continue undetected until a more serious structural problem occurs within the drainage system.
Why tree roots in drains is a serious problem
Most trees have very large root systems that are often greater than the branching area of the tree seen above ground. If you have a large oak tree in your garden, or a neighbouring garden, then imagine an underground root system that is at least equal in size, to the spread of branches that you can see above ground, and you will appreciate just how far the roots can spread.
Root systems can be very invasive, and due to their large size and spread, tree roots are capable of causing significant structural damage including damaging foundations, pushing through pavements, and having a particular liking for drain and sewer systems where they can cause blockages, serious structural problems, and subsidence.
Why tree roots grow into drains
Just as trees continue to grow above ground, tree roots are constantly growing below ground as they move through the soil in search of water and nutrients. Drain pipes in particular, contain an excellent source of water and nutrients for growing root systems: even the smallest leakage from an underground drain pipe, is enough to cause nearby tree roots to begin to grow towards this.
When tree roots reach the drain pipe they will be drawn towards any point of leakage in the drain system; the root system can then gain access to the drain pipe through any small cracks, or through loose, displaced or open joints. Once within the drain pipes the tree roots will continue to grow and develop within your drainage system. In many cases this will often continue (undetected) over a period of months, or years, until the tree root reaches a size where it begins to interfere with the flow of the drainage system, and may eventually lead to structural damage, or even subsidence, that may require costly repairs.
Problems caused by tree roots in drains
Drain blockages/poor drainage flow – one common problem caused by tree root ingress is reduced drainage flow within the drain system. As the tree root continues to grow within the drainage system, it will begin to cause a narrowing of the drain pipe, restricting the flow of waste through the drainage system. The longer the tree root has been growing within the drain pipe, the greater the root size, and the greater the disruption to the drainage system. As well as the physical blockage caused by the roots, there is the additional problem of debris building up around the roots and may eventually lead to completely blocked drains.
Early warning signs include: standing water in bottom of washing machine/dishwasher, slow flowing, gurgling, or overflowing drains – although these may also be caused by other problems such as pipe scale, or the build-up of fatty deposits.
Damage to drain pipes – As the roots continue to grow within the drainage system, they start to exert pressure within the drainage pipes. If the roots have gained entry through a crack in the pipe system, then the expansion of the roots will exert pressure on this causing it to split further or break. Within the drainage system the expansion of the roots exerts pressure on the walls of the pipes, gradually weakening them over time. Damage caused by tree root ingress ranges from split and broken pipes, up to displaced joints, collapsed pipes and even subsidence.
CCTV drain survey for tree roots in drains
A CCTV drain survey is the quickest and most cost-effective way to establish whether tree root ingress is the cause of drainage problems, or damage to your drainage system. A CCTV drain survey will quickly identify and locate any areas of damage or blockages caused by invasive roots within your drain system.
A CCTV drain survey is also useful as a pre-purchase survey for homebuyers looking to check the condition of drains to ensure there are no problems with tree roots invading the drains. Read more about CCTV drain surveys.
Repairing damage caused by tree roots in drains
The longer that the tree root has been growing within your drain system, the greater the likelihood that more serious damage may have occured. Spotting root ingress in the early stages is the key to minimising damage and avoiding costly repairs. If the CCTV drain survey highlights problems within the drainage system there are a number of possible options.
- Removal of trees – although this may seem like a quick solution, the tree roots remain below ground and may continue to grow.
- Cutting of roots – whilst this will stop the existing roots growing, new roots may eventually grow back.
- Root removal and Patch repair – if the root ingress has caused damage to a pipe joint, it is often possible to cut and remove the invasive root and then repair the damage using patch repair. One of the most effective and least disruptive methods to cut tree roots from drains is to use drain jetting/high pressure water jetting to blast through the tree roots. This provides a permanent solution, and is more cost effective and less disruptive than excavating and repairing the drain pipes.
- Drain relining – drain relining is a cost-effective option for repairing drain pipes and preventing tree root infiltration. As with patch repair, this option removes the need for disruptive excavation repairs, and also has the added benefit that it can be used to repair a whole section of drain pipe.
- Excavation – this is the most costly and disruptive option, but may be the only option if the level of damage is more severe. Excavations would normally be used when pipes have been damaged beyond the point at which they can be repaired through other methods such as drain patch repair, or drain relining.