Curt De Boer
What Causes Mystery Suken Circles on Roofs?
What do you think is causing all the “sunken circles” across this roof field? This is a roof with 6” of snow, so can the sun be doing this? Actually not. It is not melting from above, it is melting from below. This phenomenon is called heat transference. Commercial roofs are typically installed with panels of insulation held down with screws and metal plates. As the heat in your building rises, it heats up these screws which eventually heats up the plates on the underside of the roof. In fairly short order, it produces enough heat loss to melt snow inches deep. Various experts have estimated anywhere from 7-12% of heat loss with this approach. This can really add up on a large commercial building.
There are ways to mitigate this issue with fairly economical approaches. The best way is to adhere to the last layer of insulation or even better, to adhere all layers of insulation in the roof assembly. Feel free to contact us for any roof consultation, whether you are designing new or looking for solutions for your existing roof.