We are independent, professional and thorough building surveyors in Cambridge and HaverhillWe are independent, professional and thorough building surveyors in Cambridge and HaverhillWe are independent, professional and thorough building surveyors in Cambridge and HaverhillWe are independent, professional and thorough building surveyors in Cambridge and HaverhillWe are independent, professional and thorough building surveyors in Cambridge and HaverhillWe are independent, professional and thorough building surveyors in Cambridge and Haverhill

We are specialist building surveyors in Cambridge and Haverhill focusing on residential properties and listed buildings

Insider Guide: Drains

In this Insider Guide we’re going to take a look at drains, and in particular the things that can prevent them from functioning effectively, as well as simple maintenance techniques that can help to alleviate problems.

In December 2016, the Met Office predicted that temperatures in the first three months of 2017 would be higher than average, and this is a general trend that appears to be developing. Rising average temperatures can have a significant impact in many areas, not least our drains, which can in turn lead to problems with properties of all sizes.

Spring is when plants start to grow again, and growth can be stimulated by rising temperatures, especially when combined with regular rainfall. As temperatures rise, plants seek out moisture and nutrients to support their growth, and they tend to favour establishing their roots as close as possible to sources of water. It goes without saying that roots cannot penetrate solid pipes, but if there are gaps or cracks they can grow into or through these. And once they take hold they can grow rapidly, thus compromising drainage.


Clay drains are often built with a series of short pipes, which are pushed together and sealed at the joints with mortar. If there are any defects in the mortar, roots can grow through them and into the drain, and as they grow they can block the pipes and cause a build-up of waste water. And if they’re not growing inside the pipe they can grow around it and pressurise it to the point that it breaks, thus causing a leak. Build-ups and leaks can also be extremely detrimental to properties, gardens and the general environment, especially if waste is contained.

Leaking drains are also one of the common causes of subsidence. In fact it’s estimated that they account for between 15 and 20% of subsidence incidents. Leaking drains can cause the ground to soften, thus reducing the building’s load-bearing capacity so that it drops, and they can lead to fine particles in a non-cohesive soil being washed away, which reduces the volume of the soil overall. It is rare for a drain to have its joints forced open by a tree root. Roots will grow into any open joints or cracked drains, causing further damage to the drain and increased leakage.

Drains are usually laid relatively shallow in the ground. The trenches are filled with excavated materials. As the drain trench acts like a sump, drawing in ground water, the trench can erode over time, leading to consolidation of the infill, which can result in movement of the adjacent ground towards the trench.

Homeowners have a responsibility to maintain the drains within their property boundary, and it’s worth remembering that the effects of blockages or faulty pipework can be both inconvenient and unpleasant. Water can very quickly become rancid and smelly, and it can also carry infection.

Regular maintenance such as visual inspections and debris clearance around pipework will help to prevent problems with drains, but there are occasions when problems are not apparent until it’s too late. Prevention is without doubt better than cure, but if you have any concerns whatsoever about your drains, it is worth arranging for an inspection. As well as checking the current state of affairs with your drains, an inspection can also help to pre-empt future problems by identifying problem plants as well as cracks and imperfections.

During a building survey, if access to drainage inspection chambers is possible, an attempt will be made to lift covers, run taps and flush WCs so that the drain can be checked to be running clear of debris and other obstacles. It should be noted, however, that the internal drainage network will not inspected with the use of cameras and therefore no assessment will be made of the condition of the drains other than at the inspection chambers described earlier. If a further, more thorough inspection is required, then a CCTV inspection by a drainage specialist is recommended. They can also jet wash the drains to clear any debris. Here at Anglian Home Surveyors we can advise you on this.

Drains are one of the many items checked during a building survey carried out by Anglian Home Surveyors. To book a survey, please call Raphael Stipic at Anglian Home Surveyors on 01223 661439.


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