Multiple Layer Roofs

Often in our field studies we encounter multiple layer roofs.  The reasons for this vary.  Multi-layered roofs have advantages and disadvantages:

advantages:

  • Cheaper than a tear off roof installation
  • Not as messy as a tear off roof installation (less cleanup required).
  • Faster installation than a tear off roof.

disadvantages:

  • Difficult to detect any leaks
  • Adds weight
  • Gets hotter"
  • Affects inspection reports

*- Each layer of roofing has insulation properties which much be accounted for.  The "R" value is a measurement of the effectiveness of thermal insulating materials.  

R value calculator - https://www.designnavigator.solutions/CRC.php