Roofing material choices may be one of the leading contributors to urban heat island effect in addition to surface paving materials.
Light colored roofing materials including Single Ply Roofing can aid with heat deflected from buildings, and therefore reduce building cooling loads. Single Ply Roofing is also a durable roofing material that can be utilized for roofs with solar installations and green roof applications.
Most people do not give much thought to roofs and how roofing material can affect our environment, but roof coverage in our cities is commonly 25-30% which can produce noticeable ambient temperature difference between a city and rural environment of 5-10 degrees Fahrenheit.
Cool Roofs can provide cooling benefit on multiple levels. By reflecting heat, cool roofs keep the city and surrounding areas cooler, they allow for the building take in less heat and as a result reduce cooling loads on the building. Reduced cooling loads, decrease energy use which in turn reduces fossil fuel use.
Benefits of Cool Roofs:
- Insulation is more effective, when insulation gets hot it becomes 25-30 less effective
- Improved HVAC performance, where air intake temperatures are cooler 5-15 deg.
- Reduce heat flux
- Ambient air temperatures can be 15-20 degrees cooler than outside.
- Aid with reduction of peak demand energy use during hot summer days, and therefore lower base electric rate.
Types of Cool Roof membranes:
Modified Bitumen:
Asphalt based and blended with styrene-butadiene-styrene or atactic polypropylene.
Thermoset Membrane:
These include EPDM, Neoprene, and CSPE (Hypalon) and must be bonded by heat.
Thermoplastics:
These include TPO (thermoplastic polyolefin) and PVC (polyvinylchloride). These must be solvent welded with solvents such as PVC resin, plasticizers, stabilizers, pigments, and fillers.
