When determining what is causing your home to sag, settle, or sink, check its ground (its base). For the uninitiated, your home is resting on many diverse soil layers, each with different thickness and weight-bearing capabilities. These layers formed when the earth was born, nearly four and a half billion years ago. Glaciers carried and deposited certain layers, some by wind, and some by water. The architect you hired for designing and building your home might have added layers of concrete to the foundation of your building to make the foundation solid and protect it against movement of soil, a common factor during the excavation of soil. However, this is not enough to fortify the subsoil layers, lying thousands of meters under your home.
Soil layers tend to increase in strength with depth on a typical basis. In most locations, you will notice a shallow layer just underneath the surface of the soil, which is organic. This facilitates the growth of plants and other types of vegetations. You may find layers of clayey, sandy, or silty soils, depending on where you live and how the soil got there. Deep underneath these layers lies soil layer of bedrock that is very stable and dense soil or rock.
Moisture and soil
Moisture affects different types of soil layers in various ways. Clay and sandy constitute the two major types of soil.
Sand: Moisture typically does not affect the sandy soil. The water typically passes through the sand very quickly when it rains. Thanks to the inherent nature of sand, it does not expand in size when it is moist and does not shrink when it is dry.
Clay: This type of soil poses problems. It expands in size when it gets wet and shrinks when it gets dry.
What is settlement?
In simple terms, settlement is the term used to describe the movement experienced by your home when the soil underneath it can no longer support its weight. You might be thinking that what has changed to lead to this issue since the soil used to support your home perfectly.
The change of soil might be the culprit. Settlement can be caused by three common changes in soil:
1. Shrinking and drying of soil (this problem is related to clay soil)
2. Softening and wetting of the soil (clay is the culprit again)
3. Poorly compacted fill soil (blame the architect)
1. Drying and shrinking of soil
Drought: Clay soil dries out after several months or years of drought. As mentioned above, clay shrinks when it dries. In such a scenario, the quantity of soil around your house shrinks in size, creating a void space into which your home settles.
Maturing trees: You might not know that the root of a tree is typically two times the size of the tree canopy. This signifies that a tree with branches extending over your home, in all probability has roots that extend beneath your home, sucking out valuable moisture from the soil. You already know what happens when the soil dries out.
2. Softening and wetting of soil
Flood conditions and heavy rain: Clay soil holds on to the water and becomes very soft, as it gets wet. Such type of soil can be weak, causing your home to sink or shift into it. The scenario is the same when you step your feet in moist clay, and it squishes into the soil.
Poor drainage: If you allow water to stand or accumulate close to your home, it will weaken the soil by absorbing the water.
3. Poorly compacted fill soil
Removing soil from hilltops, depositing it in the hole created for the building foundation, and compressing it to create flat and buildable lots is a commonly followed procedure when building a new home. If the compression procedure is not done properly, the weight of the new building will compress it, leading to settlement.
Did you know that through settlement associated with old homes, they are also responsible for structural problems for nearly 15% of new homes? The cause of these problems is homes built on either poorly compacted fill soil or poor construction. You can solve these problems with a foundation repair job, carried out by a professional.
Other causes of settlement include shrinking and drying of soils due to leaking HVAC systems under the slab floor, commonly found in slab on grade houses. Broken and leaking plumbing lines can also cause softening and wetting of the soil.
Big shoutout to Randy from Ramco LTD. in Edmonton for providing the tips outlined in this article. Check out his business for more information!
Ramco Foundation Repairs Edmonton
9807 47 Ave NW, Edmonton, AB T9M 1P3