Which statement most accurately describes the use of rigid board insulation in a low slope roofing system?
1) Rigid board insulation is not suitable for low slope roofing systems.
2) Rigid board insulation provides excellent thermal insulation in low slope roofing systems.
3) Rigid board insulation is commonly used as a waterproofing material in low slope roofing systems.
4) Rigid board insulation is only used in high slope roofing systems.