As freezing temperatures grip most of the nation, homeowners and home inspectors alike are once again reminded of one of nature’s most destructive forces on a property: the freeze-thaw cycle. This occurs when water penetrates openings or gets absorbed into structures, freezes, melts, and freezes again. The expanding ice exerts an outward force that can cause significant problems for a wide range of materials. When this cycle is left unchecked over time, it can result in damage to asphalt, brick, stone, clay, concrete, stucco, and other materials in a variety of locations, from the foundation to the roof.
As the winter of 2021 has shown us, not only traditionally cold-weather climates can be affected by temperatures that fluctuate above and below freezing. While all homes are candidates for freeze-thaw damage, properties where homeowners have ignored the problem and not taken steps to seal vulnerable areas will likely show the most evidence of climactic-accelerated deterioration.
Certified home inspectors, like those at A-Pro Home Inspection Pittsburgh, are skilled at pointing out defects that may be the result of harsh weather. Here is a brief home inspection checklist of freeze-thaw-cycle-related problems commonly found during a detailed inspection:
Roof: Let’s start at the top. Ice dams result when a roof is unevenly heated, causing snow to melt in one spot and freeze in another—most likely at the roof’s eaves, where a ledge of ice can trap water runoff which forms over the heated part of an attic. Over a long winter, the freezing, thawing, and refreezing of ice at the roof’s ledge can cause damage to shingles, in addition to subjecting the roof and gutter system to undo stress and added weight. Trapped by the ice ledge with no means to properly drain off the roof, the melted snow can cause damage in several different ways:
- Leaking into attic spaces
- Getting into spaces between roof coverings and causing deterioration through freezing and thawing
The inspector will pay particular attention to more porous roof materials, such as fiber-cement roof tiles, which are more prone to water absorption and damage from freezing and thawing. The freeze-thaw cycle can also pose risks to roof flashing (chimneys, vents, skylights, etc.), turning minor entry points into visible cracks that, if left unrepaired, could lead to flashing failure and roof leakage.
Driveways/Walkways: The inspector will report on cracks in asphalt or concrete that may pose a tripping hazard or that could lead to more significant damage through freezing and thawing. Sealing may be recommended to prevent more extensive problems down the road. The porous nature of concrete will allow water to be absorbed. During low temperatures, this water will gather between the concrete’s smooth surface and base material. When frozen, the ice will push against the surface, causing damage over time. It is important to note that cracks can be the result of a number of factors, including impact damage, inadequate compaction at the time of pouring, tree roots, insufficient control joint spacing, and soil movement. A home’s exposed front steps are another spot where freeze-thaw problems are common.
Brick: Like concrete, brick is a porous material that will soak up water and freeze, causing chips, cracks, and breaks. Weaker, older, and brittle bricks are more susceptible to this type of damage. When examining a home’s exterior covering, an inspector may find some sides of a home (which may have
been subjected to more rain and snow than others) in worse condition. In retaining walls built with brick or other porous materials, a lack of proper draining behind the wall—needed to lessen hydrostatic pressure—can leave the structure open to freeze-thaw deterioration.
Foundation: Your inspector will check exposed masonry walls and slabs for signs of damage that may be the result of the freeze-thaw cycle, including cracks (particularly horizontal ones), chips, and breaks. Hairline cracks will be noted as defects that should be monitored so they don’t turn into major issues. Foundation cracks may be caused by a number of factors, including shrinkage due to poor mixing and curing practices; and wall settling, often resulting in vertical cracks. Your inspector will note the severity of the problem by evaluating the length, depth, direction, frequency, and location of foundation cracks.