Roofing systems and methods
According to one aspect, a roofing system comprises a plurality of insulation boards adapted for overlying a roof deck to form a layer of insulation. Each of the plurality of insulation boards has opposing planar surfaces and has a facer on at least one planar surface, and each of the plurality of insulation boards comprises polyisocyanurate foam having a first polyisocyanurate foam density. The roofing system further comprises a plurality of cover boards adapted for overlying the layer of insulation. Each of the plurality of cover boards has opposing planar surfaces and has a facer on at least one planar surface, and each of the plurality of cover boards comprises polyisocyanurate foam having a second polyisocyanurate foam density greater than the first polyisocyanurate foam density. The greater polyisocyanurate foam density provides for a compressive strength to resist deformation.
1. A roofing system, comprising:
a plurality of insulation boards adapted for overlying a roof deck to form a layer of insulation, each of the plurality of insulation boards having opposing planar surfaces and having a facer on at least one planar surface, and said each of the plurality of insulation boards comprising polyisocyanurate foam having a first polyisocyanurate foam density; and
a plurality of cover boards adapted for overlying the layer of insulation, each of the plurality of cover boards having opposing planar surfaces and having a facer on at least one planar surface, and said each of the plurality of cover boards comprising polyisocyanurate foam having a second polyisocyanurate foam density greater than the first polyisocyanurate foam density, which greater polyisocyanurate foam density provides for a compressive strength to resist deformation.
2. The roofing system of claim 1 , wherein the second polyisocyanurate foam density is between 6 lbs/ft 3 and 25 lbs/ft 3 .
3. The roofing system of claim 1 , wherein the second polyisocyanurate foam density is between 4 lbs/ft 3 and 25 lbs/ft 3 .
4. The roofing system of claim 1 , wherein the first polyisocyanurate foam density is less than 4 lbs/ft 3 .
5. The roofing system of claim 1 , wherein the first polyisocyanurate foam density is between about 1 lbs/ft 3 and about 3 lbs/ft 3 .
6. The roofing system of claim 1 , wherein the facers comprise glass fiber.
7. The roofing system of claim 1 , wherein each of the plurality of cover boards is bonded to a respective one of the plurality of insulation boards to form a roofing panel composite.
8. The roofing system of claim 1 , further comprising a waterproofing membrane adapted for overlying the layer of cover boards.