Roofing systems and methods
According to one aspect, a roofing system includes a plurality of insulation boards adapted for overlying a roof deck to form a layer of insulation. Each of the plurality of insulation boards includes a first polyisocyanurate foam having a first foam density. The roofing system further includes a plurality of cover boards adapted for overlying the layer of insulation. Each of the plurality of cover boards includes a second polyisocyanurate foam having a second foam density, and the second foam density is greater than the first foam density. Each of the insulation boards and cover boards may have a facer on at least one major surface. The second foam density may be selected to provide the cover boards with a compressive strength to resist deformation.
1. A method of constructing a roof, the method comprising:
receiving a plurality of insulation boards and a plurality of cover boards, each of the plurality of insulation boards comprising a first polyisocyanurate foam having a first polyisocyanurate foam density and each of the plurality of cover boards comprising a second polyisocyanurate foam having a second polyisocyanurate foam density, wherein the second polyisocyanurate foam density is greater than the first polyisocyanurate foam density; and
installing at least some of the insulation boards and at least some of the cover boards on a roof deck with the installed insulation boards overlying the roof deck and the installed cover boards overlying the installed insulation boards.
2. A roofing system, comprising:
a plurality of insulation boards overlying a roof deck to form a layer of insulation, each of the plurality of insulation boards comprising a first polyisocyanurate or predominantly polyisocyanurate foam material having a first foam density; and
a plurality of cover boards overlying the layer of insulation, each of the plurality of cover boards comprising a second polyisocyanurate or predominantly polyisocyanurate foam material having a second foam density;
wherein the second foam density is greater than the first foam density, which greater foam density provides for a compressive strength to resist deformation.
3. The roofing system of claim 2 , wherein:
each of the plurality of insulation boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the insulation board; and
each of the plurality of cover boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the cover board.
4. The roofing system of claim 2 , wherein the second foam density is between 6 lbs/ft 3 and 25 lbs/ft 3 .
5. The roofing system of claim 2 , wherein the second foam density is between 4 lbs/ft 3 and 25 lbs/ft 3 .
6. The roofing system of claim 2 , 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.
7. The roofing system of claim 2 , further comprising a waterproofing membrane overlying the layer of cover boards.
8. A roofing system, comprising:
a plurality of insulation boards overlying a roof deck to form a layer of insulation, each of the plurality of insulation boards comprising a first polyisocyanurate foam having a first polyisocyanurate foam density; and
a plurality of cover boards overlying the layer of insulation, each of the plurality of cover boards comprising a second polyisocyanurate foam having a second polyisocyanurate foam density;
wherein the second polyisocyanurate foam density is greater than the first polyisocyanurate foam density.
9. The roofing system of claim 8 , wherein:
each of the plurality of insulation boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the insulation board; and
each of the plurality of cover boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the cover board.
10. The roofing system of claim 8 , wherein the second polyisocyanurate foam density is selected to provide the cover boards with a compressive strength to resist deformation.
11. The roofing system of claim 8 , wherein the second polyisocyanurate foam density is between 6 lbs/ft 3 and 25 lbs/ft 3 .
12. The roofing system of claim 8 , wherein the second polyisocyanurate foam density is between 4 lbs/ft 3 and 25 lbs/ft 3 .
13. The roofing system of claim 8 , wherein each of the plurality of cover boards has a thickness, and wherein the thickness and the second polyisocyanurate foam density are selected to provide the cover boards with a compressive strength to resist deformation and protect low-density insulation layers overlaid by the cover board from damage.
14. The roofing system of claim 13 , wherein:
each of the plurality of insulation boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the insulation board; and
each of the plurality of cover boards has opposing top and bottom major surfaces and comprises a facer on at least one of the major surfaces of the cover board.
15. The roofing system of claim 14 , wherein the second polyisocyanurate foam density is between 6 lbs/ft 3 and 25 lbs/ft 3 .
16. The roofing system of claim 14 , wherein the second polyisocyanurate foam density is between 4 lbs/ft 3 and 25 lbs/ft 3 .
17. The roofing system of claim 8 , 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.
18. The roofing system of claim 8 , further comprising a waterproofing membrane overlying the layer of cover boards.