Did you know that in 1911, Oklahoma experienced record high and low temperatures in the same day? That was the Great Blue Norther of November 11, and today our state continues to experience massive temperature swings.

Oklahoma typically experiences 40- to 50-degree temperature swings between seasons. In our industry we talk about thermocycles, which occur when the weather cycles between different weather extremes. Thermocycling is stressful for a building’s masonry.

Let’s look at how this very common issue affects masonry.

Expansion and contraction

With any change in temperature, you get movement. Different types of soils move differently, but all change with the temperature. This movement causes stress in the masonry since, as you can imagine, stone and brick aren’t designed to flex.

This stresses joints in the veneer, leading to cracked or displaced mortar. The veneer itself is put under stress by expansion. Even expansion joints, which are designed to expand and contract with temperature, are put under stress by years of wear.

Frost and spalling

A hard winter can be hard on your masonry. Water gets into the masonry and freezes. This causes the surface to crack and split, or “spall.” Spalling from frost is especially problematic with brick veneers, because brick is porous and pulls in moisture that then freezes.

Once there is an exposure in the masonry, spalling only becomes worse. If moisture gets to the steel of a structure, it can lead to corrosion. This corrosion causes the steel to expand, causing severe masonry damage. We call this “rust jacking.”

The importance of maintenance

No Oklahoma building can escape the effects of thermocycles. It’s just part of where we live. However, if cracks are left unattended, the damage can get worse very quickly. That’s why we recommend rehabbing masonry as problems arise. Tuckpointing and patching up exposures will extend the life of your masonry.

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