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What Is a Soil Stack?

Even if you’ve never heard the phrase ‘soil stack’ before, there’s a good chance you’ve seen one, even if you are unaware of its purpose. A soil stack is a vertical pipe attached to a plumbing system that carries wastewater and sewage from toilets, sinks and other drainage points to the main sewer or septic system. It can also be known as a vent stack or waste stack.

You see them on the outside of buildings or protruding from the roofs of houses, offices, and just about every other building that has a plumbing system. If a property is connected to any type of sewage system, it will have a soil stack. The stack has two main purposes - to vent sewer gases up above the property and to allow waste to flow freely down and out of the building.

The soil stack regulates the pressure at which the drainage and sewer system operate. In simple terms, it stops foul smells, sewage, and dangerous gasses from flowing the wrong way through a system, therefore creating unnecessary health and safety issues inside a building.

Soil Stacks – What are the Rules?

In the UK, soil stacks are regulated by Building Regulations Approved Document H. According to these regulations, soil stacks must be installed and connected to the drainage system in a way that ensures proper ventilation and efficient discharge of waste. The stack must also be properly sealed and protected from damage, and the pipes must be appropriately sized to prevent blockages.

The Importance of Soil Stack Cleaning

As with any aspect of home or business ownership, it is important to remember that while soil stack awareness will be low and problems infrequent, it is not an entirely maintenance-free installation. Common soil stack problems include:

  1. Blockages: Due to the build-up of waste materials such as soap, grease and even hair, the pipes in the soil stack can become blocked, leading to slow drainage or a total blockage. This can be compounded in the food service industry by fats, oils and grease (FOG).
  2. Leaks: Over time, the pipes in the soil stack can become corroded or damaged, leading to leaks that can cause damage to the surrounding area.
  3. Tree Roots: Roots can penetrate the pipes in the soil stack, causing blockages and damage.
  4. Poor Ventilation: A soil stack must be properly ventilated to prevent the build-up of sewer gas. If ventilation is poor, the stack may emit unpleasant odours and even become a health hazard. Another common issue is birds nesting over the stack, blocking the vent.
  5. Poor Installation: Improper installation can cause problems such as misalignment, cracks, and leaks.

The recurrence of any problems will likely depend on how heavily the drainage system is used. Individual home soil stacks are less likely to encounter regular issues, but busy restaurants, offices, travel hubs, and multi-occupancy blocks will likely experience these complications more frequently.

Keeping the soil stack of your business premises in full operating condition is not just good preventative maintenance - it can save your business money, time and stress too. If neglected, clogged drains may result in property damage or even disruption to operations. Few of us want the costly consequences caused by an otherwise simple-to-manage issue.

Soil Stack Maintenance from Aqua Mundus

Commercial kitchens are particularly susceptible to blockages caused by fats, oils and grease, which can easily block horizontal waste pipes. This is why it is prudent and indeed legally required to have a grease trap fitted if your business cooks hot food.

Soil stack cleaning and maintenance plans are available from Aqua Mundus, helping you avoid the costly services of an emergency callout. Our qualified engineers use a range of high-tech tools such as electro-mechanical drain unblockers and high-pressure water jetting.

Our services are always fast, affordable and with full regard to the needs of your business. Call Aqua Mundus, the specialists in wastewater management, today on 01386 832205 or email for expert advice and solutions.

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