What Is Subsidence? Signs, Causes and What to Do

Subsidence occurs when the ground beneath a building loses moisture or stability, causing the foundations to move downward. When this happens, the structure above may shift, leading to cracks and distortion within the building.

It is important to note that not all structural movement is subsidence. Buildings can also experience:

– Settlement, which usually occurs shortly after construction and then stabilises

– Heave, where the ground beneath the building expands and pushes upward

– Thermal movement, caused by expansion and contraction of materials

A professional inspection is often required to determine the exact cause of movement.

1. Diagonal Cracks Around Windows and Doors

One of the most common indicators of subsidence is diagonal cracking that runs through brickwork or plaster, often starting at the corners of windows or doors.

These cracks typically follow the mortar joints in external walls and may widen toward the top.

2. Cracks Wider Than 3mm

Hairline cracks are common in many buildings and are not usually a cause for concern. However, cracks wider than 3mm (approximately the thickness of a £1 coin) may indicate structural movement. Cracks that continue to widen over time should always be investigated.

3. Doors or Windows That Suddenly Stick

If doors or windows begin sticking or become difficult to open or close, this may be caused by movement within the building frame.

Subsidence can cause distortion of door frames and window openings, preventing them from operating properly.

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4. Cracks That Are Wider at the Top

Subsidence cracks often appear wider at one end, typically forming a tapered or stepped pattern through the brickwork. This type of cracking may indicate that one part of the building is sinking more than another.

5. Wallpaper Rippling or Tearing

Interior finishes can sometimes reveal early signs of structural movement. If wallpaper begins to ripple or tear along wall junctions or around openings, it may indicate movement beneath the surface.

6. Sloping or Uneven Floors

Floors that appear to slope or feel uneven underfoot may be a sign that structural movement has occurred.

While older properties can sometimes have uneven floors due to historic construction methods, sudden changes in floor levels should be investigated.

7. Cracks in External Brickwork

Cracking in external brickwork can sometimes indicate foundation movement. These cracks often appear as stepped cracks following the mortar joints.

External cracks are particularly important to monitor as they may indicate structural issues within the building fabric.

8. Gaps Between Walls and Skirting Boards

Movement in the building structure can cause separation between internal walls, skirting boards or ceilings. If new gaps begin appearing internally, this could suggest structural movement.

9. Leaning Chimneys

Chimneys are often the heaviest part of a building structure. If the ground beneath a chimney begins to move, the chimney stack may begin to lean or separate from the main building.

This can sometimes indicate foundation movement.

10. Cracks Appearing After Long Dry Periods

Periods of prolonged dry weather can cause clay soils to shrink, particularly where large trees are present nearby. This can lead to movement in building foundations and the appearance of new cracks. If cracks appear following unusually dry weather, monitoring and professional advice may be recommended.

When Should You Seek Professional Advice?

If you notice cracking that appears to be worsening, structural distortion within the building, or several of the warning signs listed above, it may be advisable to arrange a structural movement inspection. In some instances your insurers may ask for a professional report from a Chartered Building Survey.

A qualified surveyor can assess the building, identify potential causes of movement and recommend whether further investigation is required.

Structural Movement Inspections by Dunham Hale Chartered Surveyors

At Dunham Hale Chartered Surveyors, as Chartered Building Surveyors, we provide professional inspections to assess potential structural movement and subsidence.

Our inspections help homeowners and property buyers understand whether cracking or distortion is likely to be caused by subsidence or other forms of structural movement.

Clear advice and professional guidance can help ensure that any issues are properly understood before making decisions about repair works or property purchases.

Contact use and request a quote to find out how serious the problem is.

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