What Is Frost Heave? How To Protect Your Property
The winter months can cause havoc on your home and commercial property. Frost heave refers to the upward or outward movement of the ground surface (or objects on, or in, ground) caused by formation of ice in soil. Heave normally occurs in the direction of least resistance and perpendicular to ice lenses and layers and is therefore commonly upwards.
Basically, water increases in volume by nearly 10% when it freezes, and wet soil can expand even more when frozen. When wet soil freezes the resulting pressure can cause the slab or foundation wall to shift and crack. The colder the temperature, the deeper the soil will freeze. Frost forces can lift a foundation dramatically – sometimes by several inches – leading to serious heave damage.
Frost heave inflicts considerable damage to roads, channels, foundations and subsequently, the superstructure. According to a study conducted by the Federal Highway Administration, frost heave has caused billions of dollars in damages annually to infrastructure projects in the United States alone. To prevent the detrimental effects of frost heave, it is necessary to understand how it works and identify the basic elements which lead to its occurrence. After that, proper measures can be set up to prevent it.
Understanding Frost Heave and Its Causes
What Is Frost Heave?
Frost heave is a common issue in northern climates where the ambient temperatures consistently fall below freezing during winter. Frost heave is characterized by ‘swelling soil’, meaning the lifting of a soil surface due to the expansion of water as it freezes in the underlying soil.
The problem of frost heave is worsened in areas where soil is poor and a high-water table exists. Soils that can hold and conduct water, typically containing a high percentage of fine-grained particles, are considered ‘frost-susceptible’. In these conditions, frost-susceptible soils can draw subsurface water from below by capillary action into the freezing zone above.
Frost heaving requires three things:
- A frost-susceptible soil
- A continual supply of water below (a water table)
- Freezing temperatures (that penetrate the soil)
If any one of these factors can be controlled, frost heaving can be prevented.
Common Signs of Frost Heave
Frost heave commonly leads to cracking throughout the interior walls of your home or commercial property, and less commonly, it also causes exterior cracking. You can also tell if frost heave is damaging your foundation because you will see cracks within the concrete floor slab as well as sections of slab that are tilted or displaced.
You may notice unevenness in your patio pavers or cracks and shifting in your sidewalk or driveway. You may see unevenness or cracks in your basement floor or displacement of the foundation.
Another sign you might see is bowing walls. The soil expanding around your foundation can cause the walls of your basement to push in, which causes the walls to bow in.
The Impact of Frost Heave on Properties
Frost heave can affect building foundations and other structures. Frost heave damages your office building or home’s foundation because it causes the soil underneath the foundation to shift, forcing parts of your foundation upwards while other areas do not move. This disparity leads to structural damage in your foundation, such as foundation wall cracks. Over time, this can lead to structural damage to your building, sometimes leading to the loss of your home or business.
In addition, frost heave from winter can result in uneven sidewalks. It only takes one frost heave incident to render your sidewalks dangerous for pedestrians. In some cases, the sidewalk could crack or crumble, making it difficult for people to move over it safely. Other times, frost heave could result in one side or corner of the sidewalk section sinking or lifting, making it uneven. This can lead to pedestrians tripping, dangerous accidents for those on bikes and wheelchairs or other mobility devices.
Preventive Measures to Protect Your Property
Proper Site Selection and Soil Preparation
Your ideal soil should be susceptible to frost; clay, loam, and silt are most at risk due to their relatively high moisture content. Well-drained soil is a crucial element in the prevention of frost heave, and it is necessary to address both the surface and subsurface layers to prevent the pooling of water.
In addition to benefits such as weed control and nutrition, mulch can also help to regulate the temperature of the soil by providing a blanket of insulation. Apply a layer of organic mulch such as shredded leaves, compost, straw, or bark mulch to a depth of 4 inches after the first hard frost.
Effective Drainage Solutions
Drainage and effective drainage solutions is key to preventing frost heave. Ultimately, preventing frost heave depends on the base under your concrete space, the drainage in that area, and the integrity of the surface. If the surface seals out water and/or casts it away from the surface edge, you have a better chance at avoiding issues.
Gravel or crushed stone does not hold moisture, so it makes an excellent base. Sand works as well; it takes a layer of about 4 to 6 inches to be safe. It is now the practice to place a layer of sand or rock screenings on the subgrade to prevent infiltration into the overlying ballast. Granular materials are effective against frost heave only insofar as they prevent the rapid movement of water into the zone of freezing.
Choosing the Right Building Materials
When building a new home, properly insulating basements and engineering slab on grade foundations for homes not only prevents foundations from cracking, it also reduces energy consumption and global CO² emissions.
Choose frost-resistant materials for foundation construction, such as insulated concrete forms (ICFs) or frost-protected shallow foundations (FPSFs). Properly insulate the footings, walls, and floors to mitigate heat loss and minimize temperature differences.
Another idea is to install a layer of insulation underneath the concrete when building. Putting in a layer of insulation underneath the concrete helps to prevent frost heaving from penetrating into the underlying soil and thus prevents the soil from freezing and expanding to the point where it pushes your concrete around.
Maintaining Your Property Against Frost Heave
Regular Inspections and Maintenance
Frost heave, and associated water damage, are often listed as exempt events on insurance policies. That means you need to be proactive and act when trying to protect your property from frost heave. Regular inspections and maintenance are essential.
Regularly monitor soil moisture levels to ensure appropriate conditions for preventing frost heave. Inspect and maintain drainage systems to prevent water from accumulating around the foundation. Conduct periodic inspections to identify any signs of foundation movement or cracking.
Monitoring and Responding to Changes
Taking time to monitor any changes that frost heave might have caused to your property is the first line of defense. It is recommended to check the exterior walls of your home or structure. You will want to look for cracks and signs of water intrusion.
If you do see signs of cracks or wall movement, you should contact a professional basement or foundation specialist.
Professional Solutions for Frost Heave Prevention
When to Consult with Experts
Frost heave is most common to start in January or February as the cold penetrates the ground. If you visibly notice wall cracks on interior and exterior walls, that is a typical sign that frost heave has taken over your foundation.
If you think your property has an issue caused from frost heave, you might want to contact a professional foundation repair or basement repair company for an assessment. Other experts you can contact include geotechnical engineers or construction professionals.
At BMS CAT, every has a dedicated in-house team that specializes in construction and reconstruction services. That means that should frost heave cause damage to your home or commercial property, our experts can help you determine the best course of action to restore, rebuild and recover your property.
With locations strategically located across the United States, one of our teams can serve your area best. Don’t let frost win the battle this winter! Contact us if you think that frost heave is causing damage to your property.