Clay soils are particularly susceptible to shrinking as they dry and swelling when they are rewet. Tree roots can cause significant localised effects on moisture content and will therefore seasonally effect the soil volume. In the Summer months vegetation can cause localised shrinking in clay soils although this will be partially mitigated in the Winter months when the soil is able to rewet due to a combination of weather and the vegetation being dormant.
However, it is often the case that the clay does not swell back to it’s pre-shrunk volume in the Winter and so each year the movement becomes progressively worse. Tree roots barriers can stop the tree from having a localised effect on the building, although sometimes additional measures are required to mitigate the effect of the tree.
Where significant damage has been caused by a clay shrinkage subsidence problem, it can take several years for the buildings to recover sufficiently to allow repairs to be carried out without the risk of residual cracks forming. As an alternative to underpinning, we can install a soil rehydration system to induce early recovery of the building and closure of cracks to allow repairs to proceed and reduce the cost of repairs generally.
We can carry out a full design and installation of a soil rehydration system on your behalf. Please contact us to discuss how we can help you.
Soil rehydration for subsidence remediation (M Kawecki)