Autumn, spring, summer and winter – each season has a unique effect on New York City, and transforms it into a new place. There are beautiful autumn leaves, pillowy snowbanks as a festive backdrop to the holiday bustle, trees full of blossoms in spring, and summer festivals galore.
Unfortunately, a drawback of the full four seasons experience is that the shoulder seasons get very damp, as autumn turns to winter and winter to spring. Winter’s themselves can also be damp if the temperature hovers around the freezing mark, bring a continuous freeze thaw cycle throughout the season. If a below-grade area, such as a basement or parking garage is damaged or deteriorating, water can easily penetrate the concrete. This not only leads to structural issues, but also serious moisture related problems such as mould and mildew, which can be detrimental to the health of people living in these spaces.
When construction or maintaining buildings in New York, attention must be directed to ensure moisture does not migrate to the interior of the structure. Dampproofing is a type of moisture control used in construction to do just that – mitigate the passage of water into the building. Traditionally, a vapor barrier - typically a plastic sheet - is used to resist diffusion of moisture through the wall. Technically, many of these materials are only vapor retarders as they have varying degrees of permeability.
What sort of conditions does your local climate face, and what do you do to mitigate subsequent moisture problems whilst constructing below-grade structures?