A surveyor’s guide to home maintenance – Drainage

Drainage faults are a common source of water ingress, so keeping your drainage systems in good order is essential to maintaining a dry house.

Potential issues
Rainwater drainage

  • Clogged gutters – a common issues with gutters and downpipes which is eminently preventable, but potentially serious if neglected. Vegetation build up will eventually block the passage of water, which can then overflow on to building elements. This may lead to penetrating damp.
  • Drainage pipe cracking – caused by influences like rats, roots and corrosion. Pipe cracking can lead to property damage through water ingress, particularly if the problem is situated close to the building. Increased water content in the soil can lead to subsidence if left unrepaired.


  • Drainage pipe cracking – as above, though issues in this regard are compounded by the foul nature of the contents. Cracking can lead to the escape of both water and effluvia, resulting in malodour, soil pollution and potentially even the spread of disease.

Every homeowner and tenant should be aware of the drainage infrastructure at their property. A quick walk around the plot should reveal the location of inspection chambers and the advice of a surveyor can shed more light on the likely routes and junctures if required.
Ideally, a homeowner will inspect their drains at least once a year by lifting the inspection hatch. Any blockages or material build-up should be un-clogged and washed down with a hose or removed altogether and disposed of.
A cursory inspection via the hatch will likely not reveal any pipe cracking, however. Any suspicions that there might be a leak – perhaps resulting in localised wet patches, foul smells or cracked walls – should lead you to call in a drainage expert, who can undertake a cctv survey of the drainage system to find the fault.

Rectifying Issues
Where possible, rectifying a cracked pipe should be achieved using ‘non-trench’ methods – ie. without serious excavation.
These methods include ‘cured-in-place’ pipes, which date back to the 1970s.
In short, an inverted tubular type material, saturated with resin is inserted into the pipe. An inflatable device is used to expand the material and the resin is activated using either water or uv-light. Once the resin has cured, the inflatable device can be removed and the material left behind acts as a secondary impermeable layer – allowing the drainage system to function normally.
In extreme situations, excavation would be required which is both disruptive and expensive. The best way to avoid this outcome is diligent maintenance and routine inspections – catching a fault early can literally save you thousands.

*Back to May 2016 Newsletter*

©  www.propertysurveying.co.uk     SJ