A building’s foundation doesn’t carry its own load. The design load of a building and its foundation are supported by the ground beneath. This ground beneath comprises fully, of natural earth, and as such, is affected by changing environmental factors. For a foundation to effectively support a building’s structure, measures that would ensure the ground beneath are not significantly affected by changing environmental conditions.
During a building’s design phase, a soils report is sometimes imperative. Here, the soil condition of the potential building site is determined by a geotechnical engineer. For direct foundation soil information, the geotechnical engineer collects a sample from the proposed foundation area.
Usually, for more accurate results, samples from every square foot of the soil beneath the foundation area are collected. However, such analyses are not advisable because of time and cost. Based on the results from the soil sample analysis, the geotechnical engineer will propose foundation design measures. These recommendations are put in a report format (Soil Report) and passed on to the structural engineers and those responsible for the building’s design.
The structural engineering team now designs the foundation with the soil report recommendations in mind. Ensuring that changing environmental conditions, such as moisture, will not affect the foundation. As we will discuss in this article, moisture is the principal cause of most foundation problems, with other failures mainly a result of design incompetence or natural disasters.
Water is a big factor when it comes to a foundation’s integrity. Water flowing towards the foundation can exert pressure on the foundation, leading to cracks and leaks. To prevent water from flowing towards the foundation, creating a grading plan is imperative. This is done by the civil engineering team. Notably, a grading plan needs to be according to state and local building codes.
The current standards require a 5% slope of the natural ground away from the foundation for as long as 10 feet. And a swale sloping at a minimum of 1% grade, at the 10 feet point, carries away the water. In today’s market, what is common in the design of side yards with a setback of fewer than 10 feet.
Although these standards are quite new and may not be achievable in home renovations, the most important point is that water is made to flow away from the foundation.
Mishaps like plumbing leaks can lead to water infiltration. The civil engineering team can design the perfect grading plan, however, accidents are called accidents for a reason and can be uncontrollable sometimes. Any kind of accident that results in a water leak should be fixed as soon as possible. This way, you can prevent too much moisture from leaking into the ground. Too much moisture in the ground can disrupt the soil condition.
As earlier mentioned, to determine the soil conditions, you need to consult a geotechnical engineer. The engineer gives recommendations on the soil condition discovery. In some cases, the soil amendment is the recommendation. This usually involves mixing the existing soil with a more appropriate soil that suits the potential construction needs.
In rare cases, total removal of the existing soil might be necessary. And replacing the removed soil with imported material in the foundation area. In cases like these, failing to adhere to the geotechnical recommendations can prove very costly, because the survival of the entire structure depends on it.
Soil types like clay can experience soil shrinkage and expansion, which can lead to cracks and leaks. In some cases, the engineer’s recommendation might be the need to analyze more soil samples. And of course, more soil samples equals more cost. Most homeowners might not want to incur these costs. But ignoring this recommendation might just ascertain the chances of potential foundation failure.
As in most construction projects, information is passed from one team to another. It is, therefore, necessary for every team to carefully coordinate its part, ensuring that every detail is taken into consideration. Also, every team involved in the construction must maintain a level of consistency for successful construction.
It is possible for the construction teams to consist of professionals or teams from different organizations. And if they are not on the same page, some details can go missing. It is advisable that you yield to your consultant’s recommendations with respect to hiring professionals. Clearly, because your consultant may trust the professional, or even better, both parties may have overseen a successful project together.
Design incompetence can result in structural damages and loss of life and properties. The need for the best professionals cannot be overemphasized. Every team involved must take adequate care in design and decision making. Note that a design flaw may not be immediately visible, but can result in your foundation failing over time.
Environmental changes can also cause your foundation to fail. Sadly, this is out of your control or your engineers’. Extremely harsh weather conditions can cause the soil around your foundation to lose moisture. This can lead to foundation movement and cracking.
Also, the proximity of large trees to your foundation can prove dangerous. A large tree can pull large amounts of water from the foundation soil, through its roots. Which, can again, lead to foundation movement and cracking.