Jim Fontaine, CEO, Tella Firma Foundations
The foundation of a quality constructed home or building is the foundation. While architects and home buyers are typically focused on style, design and features, a builder’s first focus – before construction even begins – is preparing the lot and laying the foundation.
But it’s not quite as simple as just clearing the land and pouring cement. A builder first needs to consider the type of foundation that is best suited for a particular project, which requires evaluating a number of factors that may steer you toward one solution or another. We call these the “Five Cs”:
- Composition of soil. Everything starts with a good soils report from a Geotechnical Engineer. This report will tell the builder the composition of the soils on the building site, including the potential activity of the soils over time at your specific site – not just the top layer of soil but also underneath. A soil test that gathers soils samples down 20-30 feet will provide the full picture. Active soils act like a sponge, expanding significantly when wet and shrinking when dry.
- Condition of lot. Are there a lot of trees and vegetation on the lot, or is the lot barren? Will you be removing a lot of trees and vegetation or adding trees and landscaping once the house is finished? Both will alter the soil conditions under the foundation, either increasing or decreasing moisture content. You also need to check the drainage and terrain – is it primarily flat or hilly? If the builder needs to level the lot by either removing or adding soil, that will also change the condition.
- Construction type. Beyond soil conditions, the type of construction and the specific location will affect the decision about a foundation. For example, some residential areas may be zoned for certain types of construction. Will your home’s exterior be masonry such as stone or brick, or will it have siding? Will the roof be tile or composite or shingle? Masonry exteriors and tile roofs are heavy materials and will increase the load on the foundation. The foundation must be designed to carry the loads of the structure and also withstand any potential movement in the soils.
- Clock. The timeframe for construction is usually a factor, particularly when considering weather and potential delays. If the builder needs to perform dirt work such as cutting or filling the existing terrain to create a level building site, that will require additional time. In addition, if soil conditions require the builder to replace active soils with more stable soils, or inject the soils with chemical stabilizing liquids, this will also add significant time to the timeline.
- Cost. The cost of the foundation you choose is a key consideration, and your decision may depend on several factors. For example, a lower-cost slab can be installed if remediation is performed to active soils, reducing or eliminating possible soil movement, but that comes at a cost. Alternatively, if the soils are not remediated and a low-cost slab is installed on active soils, there is a high probability that foundation damage could occur in the future, leading to post-construction costs. Although more expensive, the most effective foundation against possible soils movement is an elevated slab, such as a pier-and-beam system that takes soil movement out of the equation.
As you think about each of these factors, there will be a number of tradeoffs to consider. One of the main considerations is installation cost vs. quality, since a higher-quality foundation can often be more expensive and may require more time to install. While a simple slab-on-ground foundation generally is less expensive than an elevated solution, you could be sacrificing quality and creating a higher risk of foundation damage in the future.
For custom or higher-end properties, you and your builder may agree that a quality foundation is worth the investment. Even with elevated foundations, there are options to streamline the process. For example, Tella Firma’s solution offers a cost-effective elevated slab option that protects the foundation against soil movement, but is a much lower cost than a traditional pier-and-beam. In addition, utilizing Tella Firma helical piers in the construction process will allow for very fast pier installation, even in bad weather.
All of these factors are important in the decision about what foundation to use for your project. If you and your builder take time to consider the Five Cs, you will be well on your way toward building the confidence that comes from knowing your project is built on a solid foundation.