Template:Part 8 - PVC

1 Design

(See Note A-8.1)

1.1 General

1.1.1 Scope

1. The scope of this Part and the Standard shall be as described in Part 1 of Division A in this Manual.

1.1.2 Definitions

1. Words that appear in italics are defined in the Glossary.

1.2 Guarantee Term Requirements

1.2.1 RoofStar 5-year and RoofStar 10-year Guarantee

1. All projects intended to qualify for a RoofStar 5-year or RoofStar 10-year Guarantee shall comply with the requirements in this Part.

1.2.2 RoofStar 15-Year Guarantee

1. All projects intended to qualify for a RoofStar 15-year Guarantee shall comply with the requirements in this Standard for a RoofStar 5-year or RoofStar 10-year Guarantee, together with the following:
   1. An insulation overlay is required for all insulated systems, regardless of the insulation type, and overlays must
      1. be at least 6.4 mm (1/4”) thick, and
      2. possess a compressive strength of at least 690 kPa (100 psi).

1.3 All Systems

1.3.1 Use Over Sensitive Materials and Systems

1. {{hilite |Notwithstanding the requirements in Part 7 concerning heat-sensitive insulation, an insulation overlay of one or more layers is required over all flat and sloped board-type insulation, and on insulation installed on vertical surfaces,
   1. if the compressive strength of the insulation is less than 110 KPa (20 psi),
   2. if the membrane is self-adhered or will be applied with a torch flame, adhesives or hot bitumen, or
   3. if a Conventionally Insulated System supports an overburden; these roof systems must be designed with at least one layer of adhered overlay (asphaltic overlays, moisture resistant fibreglass-faced silicon treated gypsum core overlays, high-density insulation overlays, composite or membrane-laminated overlays) capable of supporting any superimposed loads on the exposed membrane, without compression or distortion of the roof system or any one of its components (see also Article 14.1.2.1).
2. The requirement to use an insulation overlay does not apply to the field application of
   1. self-adhered membranes
      1. expressly accepted by the Guarantor for application directly on specific insulation types without the use of an overlay, or
      2. expressly approved (in published literature) by the manufacturer for application directly on an insulation panel.
3. Heat-sensitive crickets used in membrane systems applied with a torch flame or hot bitumen must be overlaid using either
   1. one layer of panels,
      1. at least 12.5 mm (1/2”) thick,
      2. offset from insulation joints by at least 300 mm (12”), and
      3. continuously sealed with a flame-impervious tape along all joints with adjacent panels, or
   2. two layers of panels,
      1. each at least 4.8 mm (3/16”) thick, and
      2. offset from each other, from the adjacent layer, and from insulation joints by at least 300 mm (12”).

1.3.2 Use Over Mineral Fibre Insulation

1. An insulation overlay is not required when torch-applied membranes are installed directly on mineral fibre insulation treated with a thermofusible bitumen top surface (This exception is subject to the requirements for mineral wool insulation published in Part 7 INSULATION).
2. When an overlay board is required over mineral wool insulation, the overlay board must be a moisture resistant fibreglass-faced silicon treated gypsum core board measuring at least 12.7 mm (1/2") thick (See also 7.2 Materials concerning mineral wool insulation).

2 Materials

(See Division C: Accepted Materials)

2.1 Material Properties

2.1.1 Insulation Overlay Dimensions

1. Regardless of the type of insulation overlay, the overall thickness of insulation overlay boards shall not exceed 50 mm (2”) (See minimum allowable thicknesses are shown in Table 8.1).
2. Asphalt-coated fibreboard roof insulation adhered with hot asphalt or an asphalt-based adhesive must be asphalt-coated on the top and bottom surface (Minimum coated two-sides).
3. Fire guard tape must be 150 mm (6”) wide
   1. self-adhering modified bituminous tape acceptable to the membrane manufacturer, or
   2. Type IV fibreglass felt or No. 15 organic felt, applied with hot bitumen or cold adhesive.

Table 8.1 Insulation Overlay Minimum Thicknesses

Overlay Type	Minimum Thickness - mm (in.)
Asphaltic core	4.8 (3/16")
Moisture resistant fibreglass-faced silicon treated gypsum core	6.4 (1/4")
High-density insulation	12.7 (1/2")
Membrane-laminated overlays and Composites	As listed in this Manual
Fibreboard	As listed in this Manual
Mineral wool	As listed in this Manual

3 Application

3.1 Guarantee Term Requirements

3.1.1 RoofStar 5-year and RoofStar 10-year Guarantee

1. All projects intended to qualify for a RoofStar 5-year or RoofStar 10-year Guarantee shall comply with the requirements in this Part.

3.1.2 RoofStar 15-Year Guarantees

1. All projects intended to qualify for a RoofStar 15-year Guarantee shall comply with the requirements in this Standard for a RoofStar 5-year or RoofStar 10-year Guarantee, together with the following:
   1. An insulation overlay must be installed in all insulated systems, regardless of the insulation type.
   2. Insulation overlays must
      1. be at least 6.4 mm (1/4”) thick, and
      2. possess a compressive strength of at least 690 kPa (100 psi).

3.2 All Systems

3.2.1 Alignment of Overlays

1. See the Design requirements in Section 1 of this Part.
2. Insulation overlays
   1. should be square and should make firm, full contact with adjacent panels unless specified otherwise by the manufacturer, and
   2. must be offset at least 300 mm (12") from the joints of the insulation layer; a minus offset tolerance of 50 mm (2") maximum is permissible.
3. When multiple layers of an insulation overlay are specified, the joints between boards must be offset/staggered at least 300 mm (12") from adjacent layers and rows (See Figure 8.1. See also Part 7 INSULATION.
   

   Figure 8.1 (Click to expand)

3.2.2 Mechanical Securement

1. When mechanically attaching insulation overlay boards, the insulation and overlay boards may be fastened together as one assembly.
2. Unless otherwise indicated by the system requirements in a Tested Assembly, follow the fastener patterns set out in Part 3 SECURING the ROOF ASSEMBLY.
3. When a membrane-laminated overlay is mechanically fastened over insulation, fasteners and plates used in the field of each panel must be covered with torch-applied polyester or composite-reinforced membrane patches that extend past the edge of each plate at least 50 mm (2”).

3.2.3 Adhered Securement

1. Adhered overlays must conform to the Design requirements in Section 1 of this Part.
2. Roof system components adhered with two-component low-rise polyurethane foam must be
   1. installed immediately in wet adhesive (before a surface skin develops), applied
      1. in parallel runs or in a Z-pattern, no more than 150 mm (6”) from any edge of the board and spaced no more than 300 mm (12”) apart,
      2. to a clean, dry and contaminant-free surface, and
      3. in ribbon widths specified by the adhesive manufacturer or, in the absence of manufacturer requirements, 19 mm (3/4”) wide.
   2. properly placed and weighted in wet adhesive until cured.
3. Hot bitumen used to adhere a roof assembly
   1. must be applied at minimum rates and temperatures based on the type of product, as published by the material manufacturer and in the RoofStar Guarantee Standards for Built-up Roof (BUR) Systems, and
   2. may be applied on slopes up to 1/2:12 (for steeper slopes, select a different method of securement).