In What Circumstances is Underpinning Necessary?
October 18, 2021
Underpinning is the process of manipulating the foundation of a building and introducing new material to make it stronger than before. The process of underpinning the foundations of buildings has been around for ages, and although this process is increasingly being adopted, much of it has not changed in the way it is done. If you are unfamiliar with this term, find out here what necessitates this process and the various ways of achieving it for your building.
This is the most common reason for underpinning and the most dangerous for your building. Subsidence is the sinking of the ground under your foundation due to the movement of underground material leading to some part of your foundation collapsing or sinking deeper. This problem can be unpredictable as it is mainly caused by forces outside human interventions.
Causes Of Subsidence
Extraction of Underground Material
Prolonged extraction of minerals, water, and sand from the ground can result in a weaker soil composition, which can increase the risk of collapsing over time. When developments are done close to or top of a preexisting quarry site, the filler content holding the foundation of the house may be decomposing therefore causing the buildings to be at risk.
It is common for natural disasters such as earthquakes, droughts, and storms to cause subsidence. The ground can be split into two following an earthquake that can devastate the occupants of the specific area under attack. In areas where drought is prevalent, the soil below the foundation can dry up, forcing the ground to crack and lead to subsidence.
When an area experiences a lot of heavy rainfall, the ground is likely to experience erosion of the soil. When this continues for a long time, subsidence is probable to occur.
Depending on the extent to which your foundation has experienced subsidence, your building will give you the signal to consider underpinning. These signs can include cracks on the walls or uneven floors. When many cracks are wider at the top than at the bottom and floors are not level, your building will be screaming for help.
Change in Building’s Use
Although on rare occasions, underpinning can be done to a building to allow for a major renovation which might be attributed to a shift of the building’s use. A good example can be a building that is being renovated to accommodate heavy equipment like in the manufacturing industry.
In this case, the underpinning will be essential to strengthening the foundations of the building and preparing it for the new activities that it is going to accommodate.
Addition of Extra Space
It is more common than you think to see people interested in increasing space in an already constructed building. This can be in the form of an extra level above the building or an expansion of the basement. In this case, underpinning becomes necessary to ensure a successful build that will not overwhelm the building’s foundation.
Strengthening Surrounding Buildings
As the cities grow and new constructions go up each day, underpinning can come in handy to prevent adjacent buildings from collapsing. It is highly risky for tall buildings to be constructed next to each other without underpinning, which will encourage disturbance on an already built foundation.
Types of Underpinning Methods
The process of strengthening the foundation of a building has mainly been done by two methods for years now, but recently a new method has been adopted. These include concrete slab, screw pile, and resin injection.
This involves using concrete introduced through dug holes inside or outside the building to strengthen the foundation.
This is a more permanent type of underpinning involving concrete footing and steel piers that help return the building’s foundation to its initial position.
This is a newer form of strengthening the building that involves the injection of resin into the ground, expanding it while compressing the foundation. Although it is a quicker and less messy undertaking, it is less effective than the other underpinning methods.
Before deciding on underpinning your building, it is important to let a structural engineer assess and diagnose the problems in the building shown by the cracks and other indicators. The engineer will produce a report which will advise on and arrange for a soil test to find out if the soil is loose while suggesting a suitable solution. To complete these efforts, you require a contractor with decades of experience to successfully achieve your project.