Recognising Subsidence Before It Becomes Serious
Subsidence is the downward movement of the ground beneath your property, and it's a problem that affects thousands of homes across Cornwall every year. The good news is that subsidence rarely happens overnight — there are almost always warning signs that appear well before serious structural damage occurs.
If you own a property in Cornwall, understanding these signs could save you significant stress and expense. Whether your home sits on former mining land in Camborne, clay soils near St Austell, or the varied geology around Truro, knowing what to look for puts you in control.
The Most Common Signs of Subsidence
Diagonal Cracking
The most characteristic sign of subsidence is diagonal cracking that typically runs from window or door corners towards the corners of the building. These cracks are usually wider at the top than the bottom, distinguishing them from settlement cracks which tend to be uniform in width.
In Cornwall's traditional stone buildings, subsidence cracking may follow mortar joints in a stepped pattern rather than cutting straight through the masonry. If you notice new cracks appearing or existing cracks widening, it's time to seek professional advice.
Sticking Doors and Windows
When the ground beneath your foundations moves, it distorts the structural frame of your building. This often shows up first as doors and windows that start to stick, jam, or won't close properly. While sticking doors can have innocent causes (such as seasonal timber expansion), persistent or worsening sticking across multiple openings is worth investigating.
Gaps Around Window and Door Frames
Look for gaps appearing between window or door frames and the surrounding masonry. These gaps indicate that the wall is moving relative to the frame, which is a classic sign of differential settlement or subsidence.
Wallpaper Crinkling or Tearing
Internal signs of subsidence include wallpaper that crinkles, tears, or pulls away from the wall at joints. This happens because the plaster beneath is cracking as the structure moves, even if the cracks aren't yet visible through the decoration.
Cornwall-Specific Subsidence Risks
Mining Heritage
Cornwall's rich mining history means many properties sit above abandoned mine workings. In areas like Camborne, Redruth, and parts of St Austell, mining subsidence remains a real risk. Shallow mine workings can collapse without warning, while deeper workings may cause gradual settlement over time.
If you live in a former mining area, our resin injection ground stabilisation service can help fill voids and stabilise the ground beneath your property.
Clay Soils
Cornwall has significant areas of shrinkable clay soil, particularly in river valleys and around the St Austell china clay district. These soils expand when wet and shrink when dry, causing seasonal movement that can damage foundations over time.
Our shrinkable clay soil remediation service addresses the root causes of clay-related subsidence, including drainage improvements and moisture management.
Coastal Erosion
Properties near Cornwall's extensive coastline face additional risks from coastal erosion and cliff instability. While this isn't strictly subsidence, the effects on buildings can be similar.
What to Do If You Spot These Signs
Step 1: Document Everything
Photograph all cracks and damage, noting the date. Measure crack widths and record them — a crack monitoring programme is the first thing any structural engineer will recommend. Use pencil marks across cracks to track any further movement.
Step 2: Seek Professional Assessment
Don't panic, but don't ignore the signs either. A qualified professional can assess whether the cracking indicates active subsidence or historic movement that has already stabilised. This assessment will determine the next steps.
Step 3: Contact Your Insurance Company
If subsidence is suspected, notify your buildings insurance company promptly. Early notification protects your position and starts the formal investigation process. Our insurance claim management service can guide you through this process.
Step 4: Get Expert Help
Whether you need a drainage CCTV survey to check for leaking drains, structural masonry repairs to fix the damage, or underpinning to stabilise your foundations, getting expert help early is always the most cost-effective approach.