When there are foundation defects, this can lead to subsidence and unacceptable differential settlement, often accompanied by cracks in walls. The causes of poor foundation performance include:
- Deteriorating timber piles because of bacteria and fungus (wood rot) – this reduces pile strength
- Overloaded foundations – this could be due to structural changes to the building (such as the addition of new floors) or design and construction defect
- Movement of foundations – for example, following a period of exceptionally dry or wet weather or from a permanent adjustment of environmental conditions due to climate change
Remedial operations on failed foundations and the installation of new piles are complex and costly undertakings. That’s why your first step should always be to gain a comprehensive, accurate understanding of what’s happening with your foundations and why.
Our experts start by investigating the settlement behaviour of a building and the current condition of the foundations. This exercise forms the basis for an effective assessment and allows us to define any further intervention.
We undertake foundation investigations in accordance with the KCAF guidelines 'Foundations under buildings', which cover the investigation and assessment of timber pile and its foundations under buildings and for shallow foundations. Our investigations include the following elements:
- Archive studies
- Obtaining relevant information about the building from local authority archives
- Interpreting the information
- Visual inspection
- Identifying visible defects
- Recording the current conditions using photographs
- Levelling surveys of floors and stretcher joints
- Identifying settlement of continuous horizontal joints in brickwork
- Assessing the differential settlement of the foundations by referring to the original horizontal joints at the time of construction
- Determining the slope across the length of the building by levelling relative to the original floor
- Determining the current dimensions relative to a fixed reference point
- Precise levelling surveys
- Installing reference markers or bolts on exterior or interior walls
- Measuring the elevation of these targets on a regular basis
- Assessing the rate of foundation movement
- Inspecting foundations or timber condition
- Digging an inspection pit
- Visually inspecting the foundation for cracks and distortion
- Carrying out a dimensional survey of the foundations
- Photographing the foundations
- Determining the groundwater table
- Determining the hardness of the timber using a Pilodyn tester
- Determining the timber species, type and extent of any rot by taking pile samples and investigating them in the laboratory
- Soil surveys
- Gathering information about the subsurface structure, soil types and bearing capacity, based on cone penetrometer tests
Report and recommendations
- Assessing the elements of the foundation investigations
- Assessing the quality and performance of the foundations
- Deciding on the monitoring period
- Assessing the need for remedial works
- Making recommendations about strengthening or repairing foundations
- Making recommendations about purchasing a property
We always adhere to the local, regional or global standards when planning and implementing foundation investigations (including safety and environmental aspects) and when assessing the condition of the foundations. In fact, in many cases we have been involved developing the appropriate standards and guidelines.
We can apply our foundation investigations expertise to a wide range of commercial scenarios, including:
- The purchase or sale of residential or commercial properties
- Asset management and refurbishment, including quay walls and bridges
- Damage investigation and impartial advice in case of disputes and litigation