What is a House Foundation?

The foundation requirements for building homes can vary based on location, soil type, and design of the house, among other factors. The foundation is important because it serves as the bedrock of a home, providing stability and structural integrity. It distributes the building's weight evenly across the soil, preventing uneven settling or collapse. A well-constructed foundation also protects against moisture issues and temperature fluctuations, making it indispensable for long-term durability and safety. Today we will give a brief overview of the different areas to consider when building a foundation for a home. The topics aren’t covered in a comprehensive manner but are more intended to help build your mental model of how to assess the foundation of a house. 

Type of Foundation

Slab-on-Grade Foundation

Pros

• Cost-effective and quick to install.
• Low maintenance as there's no crawl space or basement.
• Energy-efficient because it's in direct contact with the ground.

Cons

• Not suitable for areas with freezing temperatures, as it lacks insulation against the cold.
• Difficult to access utilities once installed.
• Not ideal for uneven terrains.

Crawl Space Foundation

Pros

• Elevated off the ground, providing better protection against flooding.
• Easier access to utilities for maintenance.
• Can be less expensive than a full basement.

Cons

• Can become a breeding ground for mold if not well-ventilated.
• Less energy-efficient due to the air space.
• May require more maintenance like periodic inspections for water damage.

Full Basement Foundation

Pros

• Adds extra living or storage space.
• Easy access to utilities.
• Better energy efficiency if well-insulated.

Cons

• More expensive and time-consuming to construct.
• Risk of flooding or water damage if not properly waterproofed.
• May require more extensive soil excavation.

Pier and Beam Foundation

Pros

• Good for sites with problematic soil conditions like expansive clay.
• Elevated structure provides protection against ground moisture.
• Easier and cheaper to repair than other types.

Cons

• Vulnerable to pest infestation if not properly sealed.
• May lack the thermal mass for energy efficiency.
• Generally less stable than slab or full basement foundations.

Pile Foundation

Pros

• Ideal for buildings that require a deep foundation, such as skyscrapers.
• Can bear a very heavy load.
• Suitable for areas with poor soil quality.

Cons

• Highly expensive and time-consuming to install.
• Not practical for smaller residential buildings.
• Requires specialized equipment and expertise for installation.

The Foundation’s Soil

Soil is another important critical aspect to a home’s foundation. Soil testing is a critical step in the foundation construction process, as it provides essential information on the soil's properties, including its ability to bear weight, drainage capacity, and susceptibility to changes in moisture content. Here are the types of soil testing you should do before deciding to build your home on a plot of land.

Types of Soil Tests

Bearing Capacity Test: Determines the maximum load a soil can handle.

Atterberg Limits Test: Measures the soil's liquidity, plasticity, and shrinkage limits.

Permeability Test: Evaluates how quickly water moves through the soil.

Chemical Analysis: Checks for corrosive elements that could affect foundation materials.

Plan For Drainage and Waterproofing

Any well built home foundation should be able to handling drainage and waterproofing effectively. Poor drainage can lead to water accumulation, which may cause problems like mold, foundation erosion, and structural damage. Here’s are some common strategies we’ve seen contractors use to ensure drainage and water proofing

Drainage Strategies

Slope Grading: Grade the soil around the foundation to slope away from the home. A common recommendation is a slope of 6 inches over the first 10 feet.

Gutters and Downspouts: Install gutters to collect roof water and downspouts to channel it away from the foundation.

Drainage Channels: For more challenging areas, consider installing French drains or trench drains to redirect water.

Perimeter Drain (installed inside home): Install a perforated pipe around the foundation to collect water and divert it away from the home.

Sump Pump (installed inside home): In cases of high water tables, a sump pump can be installed to actively pump out accumulated water.

Waterproofing Strategies

Tar or Asphalt Coating: Apply a layer of tar or asphalt-based coating on the exterior foundation walls to prevent minor moisture penetration.

Membrane Installation: Attach a waterproof membrane (like a rubberized asphalt) to the foundation walls to offer a higher level of moisture resistance.

Insulation Boards: Add insulation boards over the membrane to protect it and improve energy efficiency.

Drainage Boards: Install these to guide water down to the perimeter drain.

Drain Tiles: These can be installed alongside or on top of the footing to collect and redirect water away from the foundation.

Waterproof Coatings (installed inside home): Use waterproof paints or coatings on the interior walls to prevent moisture penetration.

Interior Drainage System (installed inside home): In extreme cases, an interior drainage channel can be installed along the interior perimeter of the basement, directing water to a sump pump.

Final Certification

Once construction is completed, it's generally necessary to have the foundation inspected and certified by a qualified professional to confirm that it meets all local building codes and regulations. You can typically contact your local municipality government to set up an inspection with a site inspector.