Construction considerations for drainage systems

Drain construction plan

If you’re considering a building project, whether that’s an extension to your home or a new property entirely, the list of  things to consider can seem endless. One such thing that many don’t give much thought to is the installation or upgrade of the drainage systems servicing the new building. Often times, such systems are mandatory and so it makes sense for any construction work to take this into account so to avoid any problems in the short and long term.

Much like you’d plan what your building will look like, the drainage works need planning in advance, too. This ranges from the links between your roof drainage systems and your above ground pipes to the pipes that run below our properties. While the former is relatively simple to understand, the underground pipes can be tricky to deal with, yet is equally as important.

Drain Surveys

To decipher the layout of your underground pipes, there are two options at your disposal. The first option is a drainage survey. Thanks to advancements in technology, this process is a lot more streamlined than in years gone by. A CCTV drainage survey is an incredibly effective way of inspecting pipes and drains to get a full and accurate picture of the network of pipes underneath your property. Using remote-controlled, rod or robot-mounted cameras, drainage engineers can inspect every inch of a pipe, gathering a clear insight into its condition, features and layout.

The second option is to see if your local council has the plans or blueprints for your property – if they do have them, you may be able to use them as a reference but this could incur a fee.

Legal requirements

When it comes to legal requirements relating to drainage systems, it should be noted that you do not require planning permission for repairs that can be categorised as ‘minor’ works. However, what does and does not constitute ‘minor’ work can be affected by the particular rules and regulations put in place by the local authorities in the area.

For major works, you will often need planning permission. This includes the installation of new drains, or moving existing systems to a new location, but it varies depending on the project you’re undertaking, so be sure to liaise with your local authorities and planning commissions ahead of time.

If you’re installing a new drain near to a property line, you have a duty to inform your neighbours, under the Party Wall Act. This can minimise the risk of disputes and help keep the process efficient.

Modifying underground drains

Unlike the modifying of gutters and drainpipes, which is relatively straightforward, working on underground drains entails many risks that can cause serious issues if the proper precautions aren’t taken.

All drains must run downhill – This cannot be overstated. If your drains do not run downhill, then they will fill with wastewater without the gravity to pull it towards the sewers or your septic tank. This will lead to blockages, which will in turn leads to flooding, and thereafter damage is likely, not to mention the deeply unpleasant odours and contents within said wastewater.

You only need a slight downhill angle, but this must be consistent throughout the drains in order to avoid the aforementioned issues.

All pipes should be accessible – in the event of a blockage, you or an engineer should be able to access the drains easily and rectify the issue to prevent it worsening. You can do this by locating the inspection chambers at bends and junctions in the pipes. These chambers are the modern version of manholes, except they do not allow a person to climb into the drain to inspect it. The chambers allow for the use of rods to inspect the system – particularly useful for CCTV surveys.

It’s important to note that should your proposed works warrant any of the above procedures, drainage professionals are the best equipped to assess and advice on the situation.

Express Drainage Surveys are able to provide effective, efficient and trustworthy drain survey solutions for customers throughout London. Whether you’re undertaking a building project which requires drainage works, or you feel your current system may have a fault, we can help, using state-of-the-art technology to capture clear recordings of our findings. Simply get in touch with us to find out more.