What is ground heave?

There are many environmental, social, and financial risks involved when buying or owning an unoccupied property, including flooding, arson, subsidence, and costly renovations to name a few. However, many property owners or potential buyers, may not even be aware of a very destructive factor, known as ground heave.

So, what is ground heave? Can it be prevented? And can it be managed?

To put it simply, ground heave is essentially the opposite of subsidence. Where subsidence can cause the soil to shift lower than a buildings foundation, ground heave can cause the ground to rise.

Ground heave is likely to occur when established trees or shrubs die or are removed, therefore removing their root systems that help absorb moisture from the soil. Without these root systems, excess water can accumulate in the ground, causing the soil to expand and heave upwards. Clay soils are particularly prone to ground heave, as clay can expand extensively when wet, and shrink when dry.

Other environmental factors can also encourage ground heave, such as:

  • Pressure changes in the soil (known as ‘stress relief’) from excavations or building work
  • Change in the level of the water table
  • Leaking or overflowing pipes and water drainage systems

Some tell-tale signs that your property might be experiencing ground heave, are in fact similar to subsidence indicators.

  • Large vertical cracks running down the brickwork or beside window frames and doors (horizontal cracks are usually associated with subsidence)
  • Patio tiles or flooring that has lifted out of place
  • Doors and windows that have jarred or will not close correctly
  • Evidence of excess damp within the property
  • Bubbling or warping of wallpaper

Like subsidence, property owners can help prevent ground heave such as:

  • If you are buying an unoccupied property that will soon be demolished to make way for a new building, or you plan on building on a vacant plot, a professional survey can help determine the soil quality. By examining the quality of the soil, the type of substrate it is, and moisture content, professionals can determine if the ground can safely hold the weight of a building’s foundation.
  • Try to avoid removing any well established and deep-rooted trees or shrubs that have been planted within 40 metres of your property, as to avoid the soil from becoming too sodden.
  • Any new foundations should be set in place by professionals, as they can calculate the right depth for the foundations, and the type suited for your build.

Existing surveys of a property should mention if the building has experienced ground heave before. When purchasing an unoccupied property, your solicitor should be able to provide you with a detailed history of the property which should highlight if the property has experienced ground heave in the past. A detailed inspection by a reputable surveyor, should also highlight if the property is currently experiencing any problems directly related to ground heave. In most cases, solicitors and surveyors are legally obliged to inform you if the property has experienced ground heave, however it is always a good idea to request this information and check the details thoroughly.

A property that is currently experiencing ground heave will not necessarily be rendered uninhabitable, but it could mean that further work will need to be completed in order to make the property safe and to prevent any further damage.

If your unoccupied property is only experiencing mild indications of ground heave, the following can be done to try and prevent further damage to your property:

  • Check for any broken or leaking pipes, especially ones under your property. Have any damage repaired by a professional.
  • Reduce any excess moister in and around the property e.g. reduce any excess water from directly soaking into the ground by your foundations.

Practices such as installing raft foundations, which are used to reinforce the existing foundations of a building that is sitting on uneven or weakened soil, can be costly and should only be taken on if necessary.

If you suspect your unoccupied property is experiencing the effects of ground heave, it is advisable to pay for a professional to confirm this. Contact your insurer immediately, if it has been confirmed your property is suffering from ground heave, as they should be able to advise you on the best steps moving forward. At Guardcover Unoccupied Property, we can offer protection against unforeseen events such as ground heave.

If left un-managed, ground heave could cause significant damage to your unoccupied property. By carefully managing any existing ground heave or taking precautions for prevention, you could help reduce unwanted costs and stress down the line.

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