Settlement caused by volume reduction of clay due to loss of pore water, also called clay shrinkage, is the cause of a large part of the settlements in Sweden. Trees and dense, heavy vegetation are the root cause of the problem that many homeowners fear. What exactly is pore water loss in clay and how are the trees responsible for it happening in the first place?
How does a settlement caused by pore water sealing in clay occur?
A settlement caused by volume reduction of clay due to pore water sealing occurs when nearby tree roots extract the majority of moisture from the soil during dry hot summers. The subsequent lack of water in the ground will cause the clay to shrink and in turn the foundation under the building will sink as cavities in the ground appear.
As fall and winter return, moisture returns to the ground causing the property’s foundation to move upwards, the opposite of how it sank during the dry summer months. The risky thing is that the foundation of the property moves up and down seasonally, which can make the settlement significantly worse and more difficult to fix as the years go by.
It is important to find a suitable settlement measure that prevents further damage to the property. We at Geobear carry out a ground survey before deciding how to fix the settlement, which is an important step in the process that the experts strongly recommend is carried out before a remedial proposal ends up in the customer’s hands.
Why is a soil survey important?
A soil survey helps engineers determine, as precisely as possible, the depth of the deepest tree roots in order to effectively address settlement. Without a ground survey, the work will be done based on assumptions rather than the factual data used for verification.
If the treatment does not extend far enough or deep enough into the ground to address the entire problem, the surrounding clay is at risk of continuing to shrink, risking the settlement returning after some time. For the best possible results and a permanent solution, it is necessary that a soil survey is carried out before the work is carried out.
How is the soil survey carried out?
During the inspection, one or more soil tests are performed to determine the bearing capacity of the soil around the property. In the case of clay shrinkage, where tree roots standing around the property suck the moisture out of the clay soil and cause settlement, the location of the trees is important. Trees that stand close to the property and rise higher than the roof pose a risk of subsidence because the roots spread and can find their way under the foundation where they extract soil moisture and create cavities. Rose bushes are another plant that poses a risk as they need a lot of moisture and are often placed next to the facade where the roots grow in the ground around the foundation of the property.
Like the usual soil investigations we carry out by doing one or more penometer tests, we measure the soil’s bearing capacity. In the case of loss of pore water in clay, we also examine how the clay behaves at the different levels of the ground, whether it is hard dry scarp clay and at what depth the clay becomes moist and wet.
Geobear offers a hassle-free and cost-effective setting operation
Geobear offers you a time-efficient and disturbance-free measure specifically developed for settlements caused by pore water loss in clay. The procedure differs from how we fix settlements where the root cause has a different origin, such as in the case of moisture damage or when extensions pull away from the house.
Geobear has revolutionized the way in which settlements caused by pore water sealing in clay can be addressed, all with the innovative geopolymer grouting method. First, the geopolymer is injected into the ground, at least 0.5 meters below the deepest roots or the tree causing the settlement. The two-component solution is injected at several different levels of depth until they reach the underside of the foundation.
Almost immediately, the two-component solution will flow into all cracks and crevices, no matter how big or small they may be. Which helps prevent moisture from entering and then being extracted from the clay as the seasons change. This in turn will greatly reduce the risk of shrinkage and swelling of the clay and is our most ideal solution for settlement caused by pore water loss in clay.
Advantages of Geobear’s grouting method
- Disturbance-free, the majority of work is carried out outside the walls of the house. In the case of industries, smaller areas can be closed off at a time and work can continue.
- Time efficient, the work is completed in a few days. For residential customers, we usually complete the work on the same day.
- Accurately, our engineers specify the working surface, which means that the surrounding land is not affected. Avoid excavation and digging.
- Minimizes the risk of having to take down trees, which protects plant life and the environment.