Drainage sections rarely fail and can function freely for long periods of time. When the unmentionable does occur, the results of defective drains can be dramatic.
Drains are only usually inspected when blockages occur or as part of a survey when a property is sold. Even if the house has been sold the drains will only be investigated if the purchaser has requested a more detailed survey, for example a homebuyer’s report or building survey. In these circumstances it is usual that only the manhole covers are lifted.
When the drains fail, effluent may discharge from manhole covers or the system may fully block up. Blockages may also work their way back to the appliances inside the dwelling, with obvious unpleasant consequences.
What to do with blocked drains
The first necessity, in the event of a blockage, is to have the drainage sections rodded and cleared. The next priority should be to have the system checked, often by remotely controlled camera travelling along the drainage sections, or by pressure-testing the system.
Simply clearing the drainage sections may not be enough to solve the problem, and if your drains are blocking regularly, defects rather than stubborn effluent may be the problem. In these circumstances tests are essential. If there is a defect, in most cases it can be repaired under the terms of your household insurance.
Tree roots are the most frequent cause of damage to the drainage sections. The roots can often find a way through old clay pipe junctions and grow when they find water. The roots will then grow, creating a potential blockage and damaging pipe-work.
The best method of repair is replacement of the old pipe-work with PVC equivalent, often cased in concrete. The alternative is to remove the trees or shrubs, and clear the drains of the roots and debris. This is only an option if the drainage sections pass the pressure test.
Long-standing leakage of drainage sections can cause structural movement, so you can’t afford to ignore it.