Fixing foundation issues in your home can be worrying. Two common methods are resin injection and underpinning. Both aim to stop subsidence, but they work differently.
Resin injection is often cheaper and quicker than underpinning. At Home Subsidence Repairs we only offer resin injection.
It involves pumping expanding resin into the ground through small holes. The resin fills gaps and hardens, lifting and stabilising the foundation.
Traditional underpinning digs under the existing foundation to add new concrete support. This takes longer and costs more, but it may be needed for severe cases. Your choice depends on your home’s specific needs.
Key Takeaways
- Resin injection is a fast, cost-effective way to fix minor foundation issues
- Underpinning provides robust support for more serious structural problems
- The best method depends on your home’s unique situation and damage level
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Still worried your home may have signs of subsidence?
Understanding Foundation Repair
Foundation problems can lead to serious structural issues if left unchecked. Spotting early warning signs and knowing common causes helps homeowners take quick action to protect their property.
Signs of Foundation Failure
Watch for these red flags:
- Cracks in walls, floors, or ceilings
- Doors and windows that stick or won’t close properly
- Sloping or uneven floors
- Gaps between walls and ceilings or floors
- Bowing walls
Outside, look for:
- Cracks in brickwork or render
- Leaning chimneys
- Separated exterior walls from windows or doors
These symptoms often worsen over time. If you spot multiple signs, get a professional assessment quickly.
Assessing Structural Damage
A thorough inspection is key and most experts use tools like:
- Laser levels to check floor evenness
- Crack monitors to track movement
- Moisture meters to find damp issues
They’ll examine the whole house, inside and out. This includes the roof, walls, floors, and foundation. The goal is to find the root cause and extent of damage.
A detailed report will outline findings and repair options. It should cover immediate risks and long-term solutions. Ask questions if anything is unclear.
Common Causes of Foundation Issues
Several factors can affect your foundation:
Soil issues:
- Clay soil that expands and contracts
- Poorly compacted fill soil
- Erosion from poor drainage
Water problems:
- Leaking pipes or drains
- Inadequate guttering
- Flooding or excessive rain
Tree roots:
- Can cause soil drying and shrinkage
- May damage underground pipes
Construction faults:
- Inadequate initial foundation
- Poor building materials
Fixing these underlying problems is crucial for long-term foundation stability. Simply patching visible damage won’t solve the real issue.
Overview of Resin Injection
Resin injection is a modern method for stabilising foundations and lifting sunken concrete. This technique uses expanding resins to fill voids and compact soil beneath structures.
The Resin Injection Process
Resin injection starts with drilling small holes through the concrete slab or foundation. These holes are typically 12-16mm in diameter.
A team then injects expanding polyurethane resin through the holes.
As the resin expands, it fills voids and compresses the surrounding soil. This process can lift concrete slabs and stabilise foundations. The expansion also improves soil density and bearing capacity.
The injected resin sets quickly, often within 15 minutes. This allows for rapid structural support. After injection, the team fills and seals the drill holes.
Types of Resin Used
Two main types of resin are used in foundation repair:
- Polyurethane foam resin
- Geopolymer resin
Polyurethane foam resin expands up to 30 times its liquid volume. It’s lightweight and works well for void filling and concrete lifting.
Geopolymer resin is denser and stronger. It’s ideal for heavy-duty applications like foundation stabilisation. This resin can bear significant loads and resist water erosion.
Advantages of Resin Injection
Resin injection offers several benefits over traditional underpinning:
- Faster completion: Most jobs finish in 1-2 days
- Less disruptive: No need for extensive excavation
- Clean process: Minimal mess and debris
- Versatile: Suitable for various soil types and structures
- Cost-effective: Often cheaper than concrete underpinning
The method is also non-invasive. It doesn’t require removing floors or relocating occupants. This makes it ideal for both residential and commercial buildings.
Resin injection can address issues like subsidence, soil erosion, and concrete slab settlement. It’s effective for both small-scale repairs and large commercial projects.
Exploring Underpinning Methods
Underpinning strengthens building foundations when they become unstable. Different techniques suit various soil types and structural needs. Each method has its own pros and cons.
Traditional Underpinning
This method involves digging under existing foundations and filling the space with concrete. Workers dig small sections at a time to avoid weakening the structure. The new concrete extends the foundation deeper into stable soil.
Traditional underpinning works well for many buildings. It’s reliable and time-tested. But it can be slow and disruptive. You might need to move out during the work.
The process takes several weeks or months. It requires skilled labour and careful planning. Costs can be high, especially for large projects.
Beam and Base Underpinning
This technique uses reinforced concrete beams to spread the load. Workers dig trenches under and around the foundation. They pour concrete to form a network of beams.
Beam and base underpinning supports larger areas than traditional methods. It’s good for buildings on clay soils that shrink and swell.
The beams transfer weight to stable ground. This reduces movement and cracking. You can often stay in your home during the work. But it still takes several weeks and causes some disruption.
Mini-Piled Underpinning
Mini-piled underpinning uses small-diameter piles to support the foundation. Engineers drill holes through the existing foundation into stable ground below.
They fill the holes with steel reinforcement and concrete or grout. The piles transfer the building’s weight to deeper, stronger soil layers.
This method suits buildings on very weak or waterlogged ground. It’s less disruptive than other techniques. You can often stay at home during the work.
Mini-piled underpinning is quick and clean. But it needs special equipment and skilled operators. This can make it pricey for smaller jobs.
Comparing Resin Injection and Underpinning
Resin injection and underpinning are two methods used to fix foundation issues. Each has its own strengths and weaknesses in terms of soil types, costs, timeframes, and disruption levels.
Suitability for Different Soil Types
Resin injection works well in many soil types. It’s good for sandy or loose soils. The resin fills gaps and makes the ground stronger. Clay soils can be tricky, but resin can still work if done right.
Underpinning suits most soil types. It’s great for clay soils that shrink and swell. It also works in areas with high water tables. For rocky ground, underpinning might be the only choice.
Both methods can fail in very wet or unstable soils. A soil test is key before picking a method.
Cost Implications
Resin injection often costs less than underpinning. It needs less labour and gear. There’s no digging, so cleanup costs are lower too.
Underpinning can be pricey. It involves lots of digging and concrete. You might need to move out during the work, adding to the cost.
The final price depends on your home’s size and the problem’s scope. Get quotes for both methods to compare.
Timeframe for Completion
Resin injection is quick. Most jobs take 1-2 days. You can often stay in your home while the work happens.
Underpinning takes longer. A typical job might last 2-4 weeks. Big projects can take months. You’ll likely need to move out during this time.
Resin injection is much faster than underpinning. This can be a big plus if you’re short on time.
Potential for Disruption
Resin injection causes little mess. The process uses small holes in the ground. There’s no need for big machines or lots of digging.
Underpinning is more disruptive. It involves digging trenches around your home. This can damage gardens and paths. The noise and dust can be a bother.
After the work, resin injection sites heal quickly. Underpinning often needs more landscaping to fix the damage.
Practical Considerations
When choosing between resin injection and underpinning, several factors come into play. These include the condition of your property, soil type, and budget constraints. Let’s explore the key aspects to keep in mind.
Site Assessment Criteria
A thorough site assessment is crucial before deciding on a foundation repair method. Structural engineers will examine:
- Soil composition and moisture content
- Depth of existing foundations
- Extent of structural damage
- Nearby trees and their root systems
- Drainage patterns around the property
They’ll use tools like laser levelling instruments to measure movement. This data helps determine if resin injection or traditional underpinning is more suitable.
Selecting the Right Technique
Your choice depends on several factors:
- Severity of subsidence
- Building type and age
- Time constraints
- Budget limitations
Resin injection is often faster and less disruptive. It’s ideal for minor subsidence issues. Traditional underpinning might be necessary for severe structural problems or older buildings.
Consider the long-term implications. Resin injection can be done quickly, often in a day. Underpinning takes longer but might provide more robust support for certain structures.
Material Selection
For resin injection, the choice of resin is critical. Different formulations suit various soil types and performance needs.
The resin should be:
- Environmentally friendly
- Able to expand and fill voids
- Durable and long-lasting
Teretek® engineered resin is a popular option. It’s designed to stabilise soil and lift sunken foundations.
For traditional underpinning, concrete is the primary material. The mix must be:
- Strong enough to support the structure
- Resistant to water damage
- Suitable for the local soil conditions
