Template:All Systems - INSULATION OVERLAY BOARD EPDM

1 General

RGC accepted insulation overlay boards shall be installed over all plastic foam insulations (EPS, XEPS, Polyisocyanurate) on all adhered low slope roofing systems. When heat sensitive insulations (EPS,XEPS) are used with heat welded membrane seams an accepted overlay board must be installed.

2 Layering

Insulation and overlay board joints are to be offset/staggered 300 mm (12") from adjacent layers and rows. The uppermost layer of [insulation or] overlay board directly below membranes shall have joints that are offset/staggered from adjacent layers and rows.

3 Mechanical Fastening

Possible Wording: Refer to C5.c in this Manual for RoofStar Guarantee requirements for the application of mechanical fasteners, as they pertain to both insulation and overlay board applications.

The upper layer or overlay in a multiple-layer insulation application does not require mechanical fastening.

4 General

RGC accepted insulation overlay boards shall be installed over all plastic foam insulations (EPS, XEPS, Polyisocyanurate) on all adhered low slope roofing systems. When heat sensitive insulations (EPS,XEPS) are used with heat welded membrane seams an accepted overlay board must be installed.

5 Layering

Insulation and overlay board joints are to be offset/staggered 300 mm (12") from adjacent layers and rows. The uppermost layer of [insulation or] overlay board directly below membranes shall have joints that are offset/staggered from adjacent layers and rows.

6 Mechanical Fastening

Possible Wording: Refer to C5.c in this Manual for RoofStar Guarantee requirements for the application of mechanical fasteners, as they pertain to both insulation and overlay board applications.

The upper layer or overlay in a multiple-layer insulation application does not require mechanical fastening.

7 Using Adhesives

When membranes are adhered , at least one layer of overlay board is required over all types of insulation. In addition, the following standards, principles and information apply:

A. Two layer system: Use manufacturer's accepted proprietary adhesives per published directions, offsetting the joints from those of the insulation. Then tape joints and install second layer offsetting the joints from those of the insulation. Finally, tape joints and install second layer offsetting the joints from those of the layer below. Alternatively, the membrane manufacturer's proprietary insulation adhesives may be used to adhere accepted cover boards and insulation.

B. Single layer system: Install the insulation and cover board with the proprietary accepted adhesive. Seal over all cover board joints and wall transitions with the membrane manufacturer's proprietary self-adhered membrane tape.

8 Joint Taping

Acceptable materials for taping joints, of hot asphalt, and cold adhesive applied roof assemblies on overlay board, insulation, gypsum board, and primed plywood are minimum 150 mm (6") wide No.15 felt, 150 mm (6") wide Fibreglass roof tape, or 150 mm (6") wide sheathing (membrane breather-type to CAN / CGSB 51.32-M77). The only acceptable methods of hot asphalt installation are by back coating with asphalt, or laying with a back-coating machine expressly intended for the purpose.

For taping joints of asphalt core overlay boards, without poly film surfaces, manufacturers purpose made self-adhered modified bituminous tapes are acceptable for use with hot asphalt, torch welded and cold adhesive applied roof assemblies.