Insulation
In an age when environmental responsibility has emerged as a common value, reducing potential energy loss through the low slope roofing system is increasingly important.
A good low slope roofing system that includes proper insulation can go a long way toward reducing energy costs by diminishing the outward heat flow in the winter and inward flow of heat in the summer.
In addition to maintaining optimal thermal performance, insulation for low slope roofing systems provides dimensional stability, effective moisture resistance, and sound stability.
Types of Insulation
Roofing insulation types include:- Wood fiber
- Perlite
- Polyisocyanurate
- Polystyrene (expanded or extruded)
- Cellular glass
- Gypsum board
- Composites
When a substrate slope will not permit efficient drainage, tapered insulation will provide an effective and economical solution. Tapered insulation can extend the life of the roof assembly by eliminating problems associated with ponding water and provide positive drainage.
CSR Roofing will help determine insulation selections for your property through membrane compatibility, energy code (R-Value Requirements), insurance and code requirements regarding wind and fire, and compressive strength for heavy roof traffic and weather resistance.
Raising the R-value
Owners should be concerned about the R-value, the expression of an insulating material’s thermal resistance. The polyisocyanurate polymer is widely considered to provide the best R-value, up to R-6 per inch.
Calculating the R-value
Several organizations provide tools to calculate the R-value of the insulation in a low slope roofing system:
- Oak Ridge National Laboratories: http://www.ornl.gov/sci/roofs+walls/facts/CoolCalcEnergy.htm
- ENERGYSTAR®: http://roofcalc.cadmusdev.com/RoofCalcBuildingInput.aspx. Though similar to the one provided by the Oak Ridge National Laboratories, it does not take into consideration emissivity of the membrane, which can be important, depending on the climate.
Vapor Barriers
Moisture build-up is unlikely to occur when relative interior humidity is 80 percent or less at 70 degrees Fahrenheit. However, for areas with humidity above 80 percent, a vapor barrier that discourages moisture build-up, especially when outdoor temperatures are 40 degrees or less, usually is recommended.