Unseen but essential, the foundation silently supports the entire building’s weight. However, over time, various factors can weaken the foundation, leading to structural problems. If you suspect your home might be experiencing foundation issues, understanding underpinning – a technique used to strengthen and stabilise existing foundations – can be crucial.
In this blog, the Ora Labora team explores the causes and signs of foundation issues, along with illustrating how we approach underpinning projects to restore stability and peace of mind for homeowners.
What Causes Foundation Problems?
Several factors can contribute to foundation problems, including:
- Leaking pipes: When water leaks from pipes underground, it saturates the soil, causing it to soften and lose its load-bearing capacity.
- Trees: Trees, especially those with high water intake, can absorb significant amounts of moisture from the soil, leading to dryness and shrinkage. This creates voids beneath the foundation, compromising its stability.
- Natural ground movement: Over time, natural processes like earthquakes, floods, and droughts can cause the ground to shift, putting stress on the foundation.
- Sinkholes: These naturally occurring depressions in the earth’s surface can form due to various factors, destabilising the ground and impacting nearby structures.
- Excavation nearby: Construction activities like digging basements can remove soil, altering the surrounding soil stability and potentially affecting nearby foundations.
Signs Indicating You Might Need Underpinning:
If you notice any of the following signs in your home, it could be an indication of foundation problems and potentially the need for underpinning:
- Cracks in walls or floors: Cracks, especially those that are growing or widening, can signify foundation movement.
- Sticking doors and windows: Doors and windows that become difficult to open or close due to misalignment can be a sign of foundation settlement.
- Uneven floors: Floors that slope or become uneven can indicate uneven settling of the foundation.
What is Underpinning and How Does it Work?
Underpinning is a construction technique used to strengthen and stabilise existing foundations. It involves excavating the soil beneath the foundation in sections and replacing it with stronger materials, typically concrete. This process is carried out gradually, ensuring the building’s weight is safely transferred to the new, reinforced foundation.
Different Types of Underpinning Techniques:
Several underpinning techniques can be employed depending on the specific situation and soil conditions:
- Mass concrete underpinning: This traditional method is well-suited for shallow depths and involves excavating sections of soil and replacing them with concrete piers.
- Beam and base underpinning: This technique utilises reinforced concrete beams to transfer the building load to deeper concrete bases, offering greater support for heavier structures.
- Mini-piled underpinning: This method is ideal for situations with limited access, challenging soil conditions, or deep foundations. It involves driving small piles into the ground to transfer the load to more stable strata.
- Expanding resin injection: This newer, less disruptive approach involves injecting a special resin mixture into the ground beneath the foundation. The resin expands and hardens, strengthening the soil and lifting the settled structure.
Important Considerations Before Underpinning:
Underpinning is a complex process that requires careful planning and execution. Here are some crucial points to remember:
- Building control approval: Underpinning typically requires approval from the local building control authority.
- Structural engineer consultation: Consulting a qualified structural engineer is essential for assessing the extent of the problem, recommending the most suitable underpinning technique, and ensuring the project’s safety and effectiveness.
- Compliance with regulations: Underpinning projects must comply with relevant building regulations and safety standards, including the Construction, Design & Management Regulations (CDM) 2015 and the Party Wall Act 1996, if applicable.
If you suspect your home might have foundation problems, get in touch to schedule a structural assessment with one of our experienced engineers. At Ora Labora, we can thoroughly evaluate your situation, recommend the most appropriate course of action, and guide you through the entire underpinning process, ensuring your home’s safety and stability for years to come.
Call us on 01733 602844 or email hello@oralabora.co.uk