Frost Line Depth in Northern New England: How It Impacts Foundations and Repairs
Understanding the frost line is important for protecting your foundation and your home’s overall stability. In colder climates like Northern New England, freezing soil can shift or push against structures, especially if parts of your foundation sit above this critical depth.
Below, we’ll explain the frost line, how it affects homes in this region, and what it means for foundation repairs.
What Is the Frost Line?
The frost line is the depth at which the ground freezes every winter. Maine, for example, has a frost line with an average depth of 74 inches, while New Hampshire’s line has an average depth of 60 inches.
If your home is built above the frost line, the soil underneath it can freeze, expand, and push upward, a process known as frost heave. Anything that rests on the soil, including a shallow foundation, slabs, and footings, is at risk of movement.
Here are some potential signs that frost heave is affecting your home:
If you notice any of the above, contact Groundworks. We inspect and recommend solutions to restore your property’s safety and structure.
What Makes Frost Heave More Likely?
When your home is above the frost line, you are already at risk of frost heave. However, factors in Northern New England can make this natural phenomenon even more likely to happen:
Clay soils
Clay soils in our region retain water from rainfall, snowmelt, and flooding. This soil type expands when it absorbs water and contracts when it dries out, creating lots of ground movement that may lead to frost heave and other issues.
Freeze-thaw cycles
Northern New England is more than familiar with freeze-thaw cycles. These happen when water in the ground freezes, expands, and then thaws, which can cause soil to move, increasing the chances of frost heave.
Flooding
Homes close to rivers like the Connecticut and other bodies of water may be at risk of flooding. When floodwater saturates the ground, soil might hold onto that moisture. If temperatures drop, the soil can freeze and expand.
How to Protect Your Foundation
Having your home built above the frost line doesn’t automatically mean structural damage is imminent, but it does increase the risk. If you start to notice the warning signs discussed above, it’s important to consider foundation repair solutions like the following:
- Push piers: Push piers are driven deep into the ground until they get to stable soil or bedrock, which is well below the frost line. They can protect your property from future frost heave.
- Helical piers: Helical piers contain a steel rod with plates that a contractor screws into the ground, providing support for your foundation.
If frost heave impacts your sidewalk, driveway, patio, or other concrete surfaces, it can create uneven, unsafe conditions and lead to further cracking or deterioration. One effective solution is polyurethane foam injection, known as PolyRenewal™.
This advanced repair method lifts and stabilizes sunken or uneven concrete slabs by injecting a lightweight, expanding foam beneath the surface. As the foam expands, it fills voids caused by frost heave and soil erosion, and gently raises the slab back to its proper position, without the need for replacement.
Call On Groundworks for Foundation Repair in Northern New England
If your home’s foundation is built above the frost line, freezing and expanding soil beneath it can push upward, causing many problems. At Groundworks, we offer proven solutions to stabilize and protect your home against frost-related movement. Schedule a free, no-obligation inspection and estimate to ensure your foundation stays solid.
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