Foundation problems; causes and consequences!

Foundation problems and crack formations in buildings can spell disaster if not addressed promptly, often stemming from issues like uneven settlements, vibrations, or geological conditions. Understanding the root cause and taking immediate action, such as a professional building inspection, can prevent further damage and save on costly repairs. Dive deeper to learn about the intricacies of these issues and how they can be effectively managed.

When determining the probable cause of crack formation, we may be dealing with a stable crack ; damage that has not developed further (caused by shrinkage and creep) or an unstable crack ; damage that is developing further (e.g., due to foundation subsidence). In these cases, the cause must first be eliminated before a proper repair can be carried out.

Causes of crack formation

Increase in the groundwater level

Due to excessive water inflow, water can no longer drain through the ground, creating a more or less quicksand-like structure. The granules will seek a denser packing, causing the building to settle, resulting in cracks.

Increased groundwater level can be caused by:

Floods
Regulation by water board
Poor drainage of the site/the area around the building does not drain properly
Leaks (broken and leaking sewers, gutters or rainwater drains)

Soil accumulation

Localized ground raising creates uneven ground loads . For example, when paving is periodically raised, the piles on the facade side are subjected to additional loads, increasing the negative friction (layers of soil, as it were, cling to the piles). This causes the building to tilt toward the street.

A landfill causes a drop in the original ground level.

Stresses can be distributed through the ground in such a way that it is pushed up in another place.

Vibrations

Vibrations can cause the ground to settle locally.

Vibrations can be caused by:

Heavy road or train traffic close to the building
Piling works in the area
Earthquakes

Geological conditions

Cohesive soils are highly compressible, such as clay and loam . Due to the associated poor permeability of these soil types, settlements sometimes take decades to reach their final value.

Non-cohesive soils are generally very low-cohesion soils, such as sand and gravel. These soils are relatively permeable to water and have low compressibility. Final settlement is reached quickly. The rate of settlement is therefore related to the soil's permeability to water.

Causes of damage due to (failure to take into account) geological conditions:

Insufficient bearing capacity of the soil
Different soil layers (cohesive and non-cohesive) that can absorb different pressures
Locally undisturbed soil
The presence of a ditch system
Not properly compacted fill

Design and/or implementation errors

Common design and implementation errors:

Insufficiently deep foundation (not below the frost line)
Insufficiently sized foundation
Material defects occur during pile driving (failure/cracks in piles)
Change of function of the building

Uneven settlements due to the geometry of the structure

In a standard single-family home, the weight of the excavated soil for the basement exceeds the weight of the building that will take its place. Therefore, settlement in the basemented section is usually zero. However, settlement (and therefore damage) will occur under the non-basement section.

Uneven settlement is caused by, among other things:
Partial basement
Non-expanded extension
Concentrated loads with insufficient distribution options

Trees that are too close to the building

Roots from trees that are too close to the building can push up the foundation of buildings with shallow foundations . The tree roots locally extract water from the ground, lowering the water table. The cracks will be open in summer and closed/smaller in winter. The size and type of tree play a significant role in daily water consumption.

Recovery from foundation problems

Foundation subsidence is usually a slow but continuous process, with the crack reappearing after a longer or longer period. Unfortunately, it's not easy to determine whether the situation has stabilized or not. Sometimes, an indication can be obtained by asking questions:

How long have the cracks been there?
Have the cracks become wider recently?
Have any cracks appeared recently?
Has a foundation survey already been carried out?

In the case of a structural foundation problem, something will have to be done to the foundation.

Would you like to make an appointment for a building inspection?

The cost of a building inspection (up to 250 m²) is only €489 including VAT. We'll conduct a comprehensive building inspection and you'll receive a building report. Do you have any questions? We're happy to help and can schedule an appointment with an expert inspector right away if you wish!

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