Today in Denver, the temperature is expected to reach a high of 53°F during the day, with a low of 24°F at night. That is a 29°F temperature change within less than a 24-hour period, across the point of freezing (32°F) – or what some might call a typical Fall day here in Colorado.
The recorded temperatures in Denver from last week - look at those temperature swings!
It seems to perfect time of year to discuss the phenomena known as the Freeze-Thaw Cycle. The science behind the freeze-thaw cycle is fairly simple. When water freezes it undergoes volumetric expansion; it increases approximately 10x in size during the process of changing from liquid to solid. When liquid water is allowed to seep into the cracks and crevices of a surface, (particularly hard, porous surfaces such as concrete, asphalt and masonry) and then freezes, it exerts tremendous forces which results in cracking and spalling. In certain climates this back-and-forth daily cycle of melting ice/snow during the day followed by that retained moisture freezing at night can lead to substantial damage in short order.
You may have heard of the freeze-thaw cycle in relation to roadway damage, but what many people don’t realize is that the freeze-thaw cycle can also have damaging effects on the exterior of your property. Here are a few things you can do to limit the damage of this cycle:
1. Remove standing snow from upward facing surfaces. Our climate is typically dry enough that removing the snow promptly from sidewalks, patios and driveways will allow them to dry within a day, thus limiting the volume of water penetrating into these surfaces. Other areas to think about include the trim, shelves and ledges on the walls around your property. Masonry windowsills are particularly vulnerable. Fortunately, it isn’t too difficult to sweep these areas clear so that they have a chance to dry out before the overnight freeze. Wooden windowsills and ledges should be painted and sealed routinely prior to winter. When possible, consider cladding such surfaces in aluminum.
2. Limit the exposure of susceptible surfaces to water. There is a reason why our forebears designed homes with long roof overhangs. Consider our climate and exposure during new construction and incorporate these elements wherever possible. Awnings and carports (when structurally sound enough to support snow loads) not only make clearing off the car easier, but can protect a driveway. Keeping vegetation off of masonry walls can help limit water from wicking into these surfaces and promote faster drying.
3. If exposure cannot be limited, consider sealing the surface with a specifically-designed masonry sealer. It is easy to think of hard surfaces as watertight, but in-fact concrete, masonry, and brick are quite porous and can absorb a substantial volume of water. There are several products specifically designed to penetrate and seal these surfaces – and “exterior paint” is not one of them! Painting masonry can actually cause more problems than leaving the surface untreated, so be sure to read the manufacturer’s recommendations thoroughly and use the right product for the right material.
The freeze-thaw cycle - it’s the reason many locals say, “Colorado has two seasons winter, and roadwork.” Just remember that it’s not only our roadways subjected to this problem.
(A little tip for those of you within Denver City proper, you can report potholes and other issues here: https://denvergov.org/pocketgov/#/report-a-problem)