Roof systems deteriorate with direct exposure to changing environmental and weather conditions. Rapid changes in ambient temperature can negatively affect the roof system. A combination of cold weather and rain can significantly cool the surface of the roof making it brittle and more susceptible to punctures and tears. Low-slope roof systems can also be susceptible to damage from pollutants, UV light, and hail.
Membrane deterioration can be caused by mechanical equipment found on the rooftop. Discharge from HVAC units and grease fans can be very harmful to the roof system. Rooftop units that are improperly cleaned can result in membrane deterioration from coil cleaning detergent, algaecides, and fungicides. Overflow from the drainage pans can cause the runoff to pond on the roof area leading to deterioration and moisture infiltration.
Punctures and holes allow for water intrusion into the roof system and are a leading cause of roof leaks. Punctures are caused by a variety of factors including broken blisters, fasteners backing out the substrate, hail, blown debris, foot traffic, dropped tools, lack of proper membrane support and mechanical abuse.
Ponding is considered a problem when water does not drain off the roof within 48-hours following a rainfall. Ultimately, ponding can lead to structural damage or potential collapses since standing water is also very heavy. In cold climates, trapped water can create stress on the roof system as it expands and contracts in response to changing temperatures. Additionally, ponding water can lead to plant or vegetation growth.
Debris can be detrimental to the roof system. Debris may clog roof drains leading to improper drainage and chronic ponding problems. Certain types of debris can also puncture the roof system leaving the roof susceptible to water infiltration and leaks. In certain situtations, debris may lead to moss and mold growth as well as the nesting of small animals and birds.