Subsidence and Structural Issues.

Subsidence and Structural Issues

We have highly experienced surveyors on hand to help identify cracking and structural issues within a property.

The presence of cracks in your walls can be a major concern when they begin to appear throughout your home. Often, cracks may indicate that your home’s structure and stability is compromised, which often calls for a swift response. As property surveyors, we can assist you in identifying minor and major structural issues and help in determining whether further investigation is required. A professional should always assess any cracks in walls to determine whether it is a more serious issue. When the foundation cracks and structural issues go unrepaired, the foundation may be weak and move, putting the property at risk.

Foundation Cracks and Subsidence

The fabric of a property is considered by our surveyors when determining how it will support vertical and lateral loads.

As a result, the building’s structural components, such as roof, walls and floors are assessed to ensure they will always provide adequate strength. Although dwellings can be built in many different shapes and sizes, they must all comply with constructional principles to prevent failure when built and when faced with reasonable loads. The walls are usually laterally supported by load-bearing masonry, interior partitions, wall plates, floor joists and ceiling joists.

There are many issues that can impact external wall structures, but when we discover ongoing movement, it can cause the most distress to potential buyers and vendors. As discussed in previous topics, movement can often be caused by inadequate or defective drainage, age of the drainage is in many cases, a cause of failure. It is possible for downpipes and rainwater fittings to drain away close to a wall’s base, causing the ground beneath it to erode, which can lead to poor support for the walls above. In older properties, particularly those with clay drainage pipes, which have little protection against ground movement, defective drainage is another major cause of erosion.

In the London area, where most of the soils are at significant risk of shrink/swell of the clay, trees are often the cause behind a building structural issue. Trees are often the cause of subsidence. This is a result of moisture being taken from the ground and the tree roots. It has been found that trees with fine and long root structures cause the most damage regarding building subsidence. Recent surveys have found that Oak, Willow, Sycamore, Ash, Plane and Poplar are the most common trees related to building subsidence.

At Arbery Surveyors, we can help you identify tree species and the course of action to follow once the problem has been highlighted.

Rectifying Subsidence

The most common remedial solutions for property subsidence are underpinning, screw piles, or resin ground injection. The ground conditions determine which option is the most suitable. Screw piles are often a preferred option where there is trees or clay conditions and the screw piles can be installed to a depth where they are unaffected by clay shrink and heave and below root systems. Resin ground injection would be suitable where the ground is porous, and the resin can flow. Traditional concrete underpinning is a proven option that can be used in many applications. Sometimes though depending on the ground conditions and the proximity of neighbouring properties the depth of excavation can be challenging in terms of health and safety.

Upon finding ongoing movement by our Surveyor, a Structural Engineer may need to conduct further investigation and may need to dig trial pits along the foundations for them to examine the subsurface for stability. The Surveyor may recommend the commissioning of a structural engineer if the movement is suspected so that they can provide a structural adequacy certificate which may be requested by building insurance.

Cracks forming in walls 

There is a possibility that hairline cracks that appear over doors and windows can be a result of seasonal movement. This is common in new buildings. The fact remains, though, that properties, regardless of their age, can move and shift over time. There are a few signs that can help you determine whether you’re dealing with a hairline crack in the wall or one that is caused by foundation movement, so take a stroll around the property, observe and look for the following signs:
  • Roofs that are sagging
  • Cracks in brickwork (diagonal following the brickwork and vertical, with snapped headers)
  • It is common for gaps to form around windows and doors
  • Flooring that is not level
  • External walls that are bowing or leaning

If you would like more information about cracks in walls, cracks caused by foundation movement and subsidence, please feel free to contact our team today.

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