Subsidence Repair
Subsidence occurs when the ground beneath your property sinks or compresses, causing the structure to settle unevenly. This can happen gradually over time or more rapidly depending on the cause. Unlike ground heave (where the ground rises), subsidence typically results from soil compression, water loss, tree root activity, mining activity, or poor drainage. The movement can cause visible cracks, sloping floors, and structural misalignment if left untreated.
Common causes include clay soil shrinkage due to drought or water loss, tree roots extracting moisture from the soil (particularly willows and oaks near foundations), leaking water pipes causing soil erosion, poor surface water drainage, mining subsidence in certain regions, and inadequate original foundation depth. Sometimes multiple factors work together. Our comprehensive surveys identify the specific cause affecting your property so we can recommend the right treatment.
We use a combination of techniques including visual structural surveys to identify cracks and damage patterns, measured crack monitoring to track movement over time, soil investigation through boreholes to assess ground conditions, and sometimes ground radar technology to detect changes beneath the surface. We also review historical data about the property and examine any previous insurance or surveyor reports. This thorough approach allows us to confidently identify whether subsidence is occurring and establish its cause.
Historical subsidence has stabilised and is no longer causing ongoing movement, i.e. the damage occurred in the past but the property has settled. Active subsidence means the ground is still moving, indicated by new or widening cracks and ongoing structural changes. This distinction is important because active subsidence requires treatment to stop further movement, while historical subsidence might only need cosmetic repairs. Our monitoring service helps determine whether subsidence is active or stable.
The timeline depends on the cause and severity. If the issue is related to drainage or tree management, improvements can be seen within months. If underpinning is required, the work typically takes several weeks to several months depending on the foundation depth and property size. For some cases, we monitor movement over 12 months before commencing treatment. We’ll provide a clear timeline during your initial survey based on your specific circumstances.
Not necessarily. Many subsidence issues can be resolved by addressing the underlying cause by improving drainage, removing problematic tree roots, or fixing water leaks can halt movement without underpinning. However, if ground conditions are severely compromised or movement is extensive, underpinning may be the most effective solution. We’ll only recommend underpinning if it’s genuinely needed, and we’ll explain the reasons during your survey.
Ground Improvement
Ground improvement refers to techniques that enhance the load-bearing capacity and stability of soil beneath your property. This might involve compacting loose soil, removing poor-quality material and replacing it with better-quality material, improving drainage, or injecting stabilising compounds. Ground improvement prevents future subsidence, reduces differential settlement, and can extend the life of your foundations. It’s particularly important for properties built on poor soil conditions or in areas prone to ground movement.
Our surveys include soil investigation through borehole sampling to assess ground conditions at various depths. We examine factors like soil type, density, moisture content, and bearing capacity. If we find that the soil isn’t providing adequate support for your property’s current or future needs, ground improvement works will be recommended. This might be preventative (to avoid future problems) or corrective (to address existing settlement or movement).
Our methods include soil replacement (removing poor material and installing engineered fill), soil compaction using specialist machinery, vibro-compaction for deeper improvement, jet grouting or chemical grouting to stabilise and strengthen soil, and drainage installation to control water movement. The choice depends on ground conditions, depth, and the specific issues affecting your property. We always recommend the most cost-effective and least disruptive approach for your situation.
Ground improvement is generally less disruptive than underpinning as it doesn’t require deep excavation beneath the building. However, depending on the method used, there may be some ground-level excavation, temporary access requirements, and machinery operation. We work closely with you to minimise disruption, schedule work at convenient times, and explain access and noise implications upfront. Most ground improvement projects can be completed within a few weeks.
Re-Levelling
Re-levelling involves carefully raising a property’s structure back to its original level (or close to it) after it has settled or subsided. This is done hydraulically using controlled jacking to gradually lift the building while maintaining structural integrity. Re-levelling is considered when a property has settled significantly, causing sloping floors, jamming doors and windows, or visible structural misalignment. It’s often combined with underpinning or ground improvement to ensure long-term stability once the property is re-levelled.
In most cases, we can achieve 80-90% re-levelling, bringing the property back very close to its original level. Complete 100% levelling isn’t always possible or advisable since raising a property too much can cause new structural stresses. Our engineers assess how much re-levelling is safe and practical for your specific building, always prioritising structural safety. The amount of movement needed is determined during your survey based on the building’s age, construction type, and condition.
When carried out by experienced engineers using modern hydraulic equipment, re-levelling is safe and shouldn’t cause damage. We use multiple carefully-positioned jacks to lift gradually and evenly, monitoring progress constantly. Preparations include pre-strengthening weak areas and installing temporary support as needed. However, re-levelling will typically cause some cracking in plasterwork and internal walls as the structure adjusts (cosmetic issues that can be repaired after stabilisation). We’ll discuss these implications in detail before work commences.
The actual re-levelling operation typically takes several weeks, depending on how much lifting is required and the complexity of your property’s structure. The process must be done gradually and carefully to avoid shocking the structure. Preparation work (including ground improvement or underpinning installation) may add additional weeks. Complete projects from preparation through to final stabilisation usually take 2-4 months. We’ll provide a detailed timeline specific to your property during the planning phase.
This depends on the extent of the work and your personal comfort level. For major re-levelling projects, we typically recommend temporary relocation as the building will be under jacks and significant work will be underway. However, for minor works, some residents choose to remain. We’ll discuss this with you and explain the practical implications. Your safety and comfort are our priorities, so we’ll help you make the best decision for your situation.
Underpinning
Underpinning is a structural reinforcement technique where the foundation is extended deeper into the ground to reach more stable soil layers capable of properly supporting the building. It’s done by excavating beneath the existing foundation in stages, installing support structures (usually reinforced concrete foundations), and gradually transferring the building load to the new, deeper foundation. Underpinning is one of the most effective solutions for severe subsidence, poor soil conditions, or when a building needs additional structural support.
Underpinning is recommended when subsidence is severe and ongoing, when original foundations are inadequate for current or future use, when soil conditions are so poor that other methods won’t suffice, when you want to extend or significantly alter a building (requiring increased load capacity), or when other repair methods have proven ineffective. Not every foundation problem requires underpinning and we only recommend it when it’s genuinely the best solution for your specific circumstances.
Underpinning depth varies depending on soil conditions revealed through investigation. We bore to find stable soil strata, which could be 1-2 metres down for some properties or considerably deeper (sometimes 10+ metres) for others. Factors include the property’s location, local geology, current foundation depth, and the load the building needs to support. Our engineers will determine the optimal depth during your survey to ensure long-term stability without unnecessary extra cost.
Common methods include traditional mass concrete underpinning (excavating and infilling in stages), reinforced concrete underpinning (for higher loads), pile underpinning (using driven or bored piles to support the structure), and resin injection underpinning (a less invasive chemical method for certain situations). Each method has advantages depending on ground conditions, building type, and depth requirements. We’ll explain which method is most suitable for your property and why.
Underpinning is a time-intensive process. Projects typically take 6 weeks to several months depending on foundation length, depth, building age, and building type. Work must proceed methodically in sections to maintain structural stability. It is generally not possible to underpin the entire foundation at once. For large properties or complex buildings, projects can extend 3-6 months or longer. We’ll provide a realistic timeline during your survey based on the scope of work required.
Subsidence repairs, including underpinning, are typically covered under buildings insurance policies with most standard policies covering subsidence protection. However, coverage depends on your specific policy terms and whether subsidence is included. Some policies have conditions (like timber treatment or drainage maintenance). It’s important to check with your insurer before work begins. We can provide quotes and documentation to support your insurance claim. Your insurer may require us to follow specific procedures or use approved contractors.
For extensive underpinning work, we typically recommend temporary relocation as the work is disruptive and prolonged. However, for limited underpinning of specific sections, some residents remain in the property depending on personal preference and practicality. During active underpinning phases, there will be noise, vibration, and restricted access to certain areas. We’ll discuss relocation options and provide a detailed work schedule so you can make an informed decision about what’s best for you and your family.
General FAQs
Costs vary widely depending on the problem’s severity, the property size, ground conditions, and the repair method required. Minor repairs might cost a few thousand pounds, while major underpinning can cost £20,000 to £100,000+ for larger properties. We provide detailed quotations after surveying your specific situation. Most repairs are covered by buildings insurance.
Completing professional foundation repairs actually protects your property value and typically improves your insurance situation. Once work is certified and completed, insurers view your property as lower risk. Leaving foundation problems unrepaired is far more likely to cause insurance complications or refusals.