Subsidence: The 5 Biggest Causes And How To Reduce The Risk

We do not need to be a geological professional or a civil or structural engineer in order to understand and digest the subsidence and its main causes. 

If we want to define it in simple words then we can say subsidence is basically a downward shifting of the ground which can impact the buildings in horrible ways. 

If a geological professional or a civil or structural engineer is informing you that your home is suffering from subsidence, It indicates that your home is sinking. 

How will you understand that the structure is suffering with subsidence? 

Structures or walls that bend, bow, lean or are cracked will be the best identifying signals of a subsiding wall or structure. 

Let us see here the top 5 reasons that we should watch If we are worried about our home or office subsiding 

1. Water Erosion 

2. Tree roots and vegetation 

3. Reactive clay 

4. Poor workmanship 

5. Vibrations 

Water Erosion 

Figure 1 : Water erosion subsidence 

Water erosion is basically considered as one of the common reasons for subsidence. The erosion of foundational soil usually occurs when there is continuous flow of water pools into the soil. 

It results in the soil aerating and weakening. We must note here that water will find its way into and below the footing of buildings from storm water drains, burst surge pipes or mains inlet pipes that are cracked and leaking. As the soil starts to absorb more and more water, it starts to subside and causes structural challenges in the buildings. 

Tree roots and vegetation

Figure 2 : Tree roots and vegetation subsidence 

It will cause subsidence by removing the water out of the soil. 

We must note here that If a particularly thirsty large plant or any new tree has been placed near our home, what will happen ? 

It will undermine the balance of the soil and hence our home sits on as it will suck the water out of the ground. It will be aerated and unstable and it will cause our buildings to subside because the plants will draw water out of the soil. 

Sickly vegetation could also be something to be very careful of as it will have many roots and hence it will take up a lot of space underground and cause the soil to aerate and in hence, subside. 

Reactive clay 

Figure 3 : Reactive clay subsidence 

It is basically very dense soil that contracts or expands according to the changes in the seasons through the entire year. 

Reactive clay will absorb the moisture and hence will expand during the cold seasons. Similarly, it will contract as it dries up during the hot seasons. 

Such movement naturally comes according to the changes in the weather but reactive clay will be a burning issue when new elements will be introduced to the environment. 

The addition of trees and plants, a new drainage system or any modified or renovated drainage system may draw more water than usual out of the reactive clay. 

As water will be drawn out of the clay by such changes and hence there might be dramatic subsidence that can occur and in turn it will ruin the structural foundation of our buildings. 

Poor workmanship

Figure 4 : Poor workmanship subsidence 

Negligence and human error will be the prime cause of poor workmanship and It is considered as one of the major causes of the subsidence. 

If the contractors or the builders are in a hurry to finish the project or job, they will cut the corners wherever they will be able to cut. Many contractors or the builders don't bother pouring trenches & compacting the ground perfectly in order to develop the stable footing. 

We must note here that, without compacting properly, we will have aerated, weak or voided soil that can subside very easily further down the track. We have observed so many areas where the contractors or the builders also avoid installing the quality drainage. It results in the water leaks that soak into soil and cause erosion & eventually subsidence. 

Vibrations

Figure 5 : Vibration subsidence 

We must note here that if there is constant vibrations in the ground, it will shake the soil to the level where it will become aerated and hence unstable. 

Following activities, as mentioned below, can cause subsidence as there will be consistently vibrations in the ground. 

 

1. Activities nearby construction sites where continuously heavy earth moving equipment will be working or other construction work will be executing. 
2. Activities at main roads where continuous heavy trucks, other heavy vehicles and cars pass. Activities at airports where there will be planes weighing thousands of tons land and take off. 
3. Activities at heavy industrial activities such as mining.
4. Heavy train consistently running at high speed.

Therefore, we should consider the above condition to build our homes or offices accordingly. However, if we are having any issues related to subsidence, we can connect with Mainmark, The Mainmark Group to find out the best solutions for the same.