Foundation Repair Guidelines for Homeowners – Groundwater Monitoring

This article is the third installment of the Foundation Repair Guidelines for Homeowners. Now that we’ve covered site analysis and repair proposals, it’s time to discuss the importance of groundwater management, not only as an essential component of a comprehensive foundation repair plan, but as a proactive approach to prevention. of foundation damage.

Groundwater management is essential to keep your cellar or basement dry, and to prevent resulting damage to your foundation. Structures below grade (mezzanine basements and slabs on grade foundations) are designed to resist a combination of hydrostatic (water) and soil pressure (the pressures exerted on a wall by surrounding soils).

Hydrostatic pressure on a foundation wall occurs when the water table rises above the foundation at any point. So the walls located below the groundwater level, also known as the water table, experience this pressure. Groundwater levels, and consequently hydrostatic pressure, can vary seasonally (usually higher in the spring), daily, or even hourly under certain circumstances. Hydrostatic pressure can be sporadic based on changes in groundwater elevations or continuous in areas where groundwater elevation remains present in the foundation wall or floor slab.

When full hydrostatic pressure is exerted on the foundation, it remains constant until excess water drains through the soils surrounding the foundation or slab. This additional earth pressure can affect the structural design of your home’s foundation or slab. However, groundwater levels are not the only factors that contribute to hydrostatic pressure. Certain types of soil, saturated clays and silts, for example, exert lateral pressure on foundations equal to their density and can exceed purely hydrostatic pressure when groundwater is present.

Foundation problems and cellar or basement leaks are often not considered by most homeowners to be preventable with routine maintenance; however, a large number of foundation repairs and basement waterproofing problems can be prevented through proper stormwater management and surface drainage. Improper groundwater drainage can lead to pooling of water around exterior foundations, creating hydrostatic pressure on foundation walls.

Hydrostatic pressure can lead to foundation damage, allowing foundation walls to crack, drift inward, settle vertically, and allow water to seep into the basement or basement of your home. Most basement water problems are not basement problems at all, but groundwater drainage and control problems. Therefore, it is better to manage water flow to alleviate or eliminate foundation damage, or basement seepage, than to rely on waterproofing or foundation repair alone. Groundwater can enter your home in many ways. Common examples of water penetrations are cracks in foundation walls and floor slabs, tie rods, or pipe penetrations.

Groundwater management begins with an assessment of existing site conditions. As the owner, you have two fairly broad options for assessing the health of your site. You can perform routine maintenance yourself to alleviate potential foundation damage and control basement seepage, or seek the professional advice of a contractor who specializes in foundation repair and groundwater control. In the event of foundation damage, the best course of action is a professional evaluation of both the foundation and the site conditions that are contributing to the foundation damage.

There are numerous methods that can be used for groundwater control depending on existing site conditions. The simplest solutions to relieve or eliminate excess hydrostatic pressure present in your foundations involve passive groundwater control. Various passive methods of groundwater control include proper grading to control surface runoff, extension of downspouts, granular fill including installation of foundation drainage, and proper grading of paved and concrete surfaces.