10 Aug How Dry Summers Can Lead to Foundation Movement
Long, warm summers may be welcome, but extended periods of dry weather can create problems beneath the surface. When rainfall levels remain low for weeks or months, the soil supporting a property can lose moisture, shrink and move. For some buildings, this can result in cracking, uneven settlement and subsidence.
Properties built on clay-rich soils are particularly vulnerable. These soils are found across large parts of England, especially London, the Southeast and areas of the Midlands, and can change significantly in volume as their moisture content rises and falls.
Understanding why this happens, recognising the early warning signs and seeking specialist advice can help property owners address foundation movement before the damage becomes more serious.
Why Does Dry Weather Affect Foundations?
A building’s foundations are designed to transfer its weight safely into the ground. Their stability therefore depends not only on the design and depth of the foundations, but also on the condition of the supporting soil.
During a prolonged dry spell, moisture evaporates from the ground. Plants and trees also continue drawing water through their root systems. As moisture levels fall, some soils contract.
Clay is particularly sensitive to these changes. It can expand when wet and shrink as it dries, creating what is often described as a shrink–swell cycle. If the ground beneath one section of a property shrinks more than another, the foundations may move unevenly. This is known as differential movement and can place stress on walls, floors, doorways and other parts of the structure.
Recent UK Weather Highlights the Risk
The weather experienced across the UK during summer 2026 provides a timely example of how quickly heat and limited rainfall can affect ground conditions.
Provisional Met Office figures covering 1 June to 15 July show that the UK’s mean temperature was 1.8°C above the seasonal average. England was particularly warm, with its mean temperature running 2.4°C above average.
Conditions became particularly dry during July. Environment Agency figures published on 16 July showed that England had received just 3% of its long-term average rainfall for the month so far. Less than 1mm of rain was recorded anywhere in England during the week ending 14 July, and soils were described as much drier than average across every part of the country.
These conditions do not mean that every property will experience subsidence. However, sustained high temperatures and declining soil moisture can increase the likelihood of shrinkage in clay-rich ground, particularly around properties with shallow foundations or nearby mature trees.
Why Are Clay Soils More Vulnerable?
Clay particles hold water within their structure. When the soil is moist, it expands. When it dries, it contracts.
The amount of movement depends on several factors, including:
- The type and depth of clay beneath the property
- The length and severity of the dry period
- The depth and design of the existing foundations
- The presence of trees and large shrubs
- Local drainage conditions
- Previous ground disturbance or excavation
How Trees Can Increase Soil Drying
Trees can contribute to foundation movement by drawing moisture from the surrounding ground. During prolonged warm weather, mature trees may remove significant amounts of water from the soil. Where roots extend close to or beneath a property, this can lead to uneven ground shrinkage and increase the risk of subsidence.
Removing a tree is not always necessary or appropriate. In some cases, a tree root barrier can be installed between the tree and the property to help redirect root growth and reduce moisture loss around the foundations.
At U&M Group, we can design and install specialist tree root barriers to help protect foundations while allowing established trees to remain in place. Each installation is assessed individually to ensure the solution is suitable for the property, soil conditions and surrounding vegetation.
Signs of Possible Foundation Movement
Not every crack is evidence of subsidence. New plaster can develop small cracks as it dries, and buildings naturally experience a degree of thermal and seasonal movement.
However, property owners should pay particular attention to:
- Diagonal cracks around windows and doors
- Cracks wider than approximately 3mm
- Cracking visible in the same area inside and outside the building
- Doors or windows that begin sticking unexpectedly
- Gaps appearing around frames, floors or skirting boards
- Floors becoming uneven or noticeably sloped
- Wallpaper tearing or rippling without signs of damp
- Cracks that appear suddenly or continue to widen
The location, shape and timing of a crack are often more important than its appearance alone. Monitoring and professional assessment can help establish whether movement is active, historic or purely cosmetic.
What Should You Do if You Notice Movement?
If you are concerned about your property, avoid carrying out cosmetic repairs immediately. Filling and redecorating a crack may hide useful evidence without resolving the underlying cause.
Instead:
– Record the damage. Take clear, dated photographs and note when the crack first appeared.
– Check for related problems. Look for leaking drains, damaged pipework, blocked gutters or nearby vegetation.
– Monitor changes. Note whether cracks widen, spread or change with the seasons.
– Contact your insurer. Your buildings insurer should be informed promptly if you suspect subsidence.
– Arrange a professional assessment. A structural engineer or specialist foundation contractor can investigate the cause and recommend the appropriate next steps.
Not every case of movement requires underpinning. Drainage repairs, tree management, monitoring or localised structural repairs may sometimes be sufficient.
Protect Your Property During Dry Weather
Dry summers do not automatically mean that a property will experience subsidence. However, prolonged low rainfall can increase the risk where shrinkable clay, nearby trees, shallow foundations or existing structural weaknesses are present.
Early assessment is important. Identifying the cause of movement before it becomes more advanced can reduce disruption, prevent unnecessary work and protect the long-term stability of your property.
If you have noticed new cracks, sticking doors or other signs of foundation movement, contact us today. Our experienced team can assess your requirements and provide specialist advice on underpinning, piling, tree root barriers and structural repair solutions.