Materials:Snap Rib (Vicwest)

Manufacturer: VICWEST

Contact Address: See Membership List in Section 1.

Product Group: SNAP LOCK SEAM METAL ROOF SYSTEM – SNAP RIB

DESCRIPTION

VicWest SNAP RIB is a 300 mm (12") wide by 25 mm (1") deep by .61 mm (0.024") thick Exposed Metal Roof Panel. The panel can be applied to solid wood or steel decks with or without insulation. The panel can be supplied with or without 6mm (1/4") x 18 mm (3/4") screw slots for thermal expansion capabilities. SNAP RIB is attached to the substrate deck with hidden pancake head fasteners and the side seams snap together with or without side seam sealants to form a strong interlock without the use of a mechanical seaming device. Panels are available in galvanized steel, galvalume steel, Modified Silicone Polyester and Kynar Metallic painted finishes. Normal sheet lengths range between 1.2 m (4') to 18 m (60') and lap joint details are available where longer roof lengths are required.

PART 1 - GENERAL

The roofing assembly / material information published in the RCABC Roofing Practices Manual DOES NOT represent a complete set of the manufacturer's published data, nor does it represent a fully detailed specification. The preparation of a detailed specification is the responsibility of the design authority and that authority should contact the manufacturer’s technical representative for full technical, specification and product application information.

1.1 DESIGN STANDARDS

.1 Design roof cladding in accordance with the latest edition of:

.1 CAN / CSA – S 136 for the Design of Cold Formed Steel Structural Members.

.2 Specified loads, load factors and load distributions shall be in accordance with the latest British Columbia Building Code, unless otherwise stated.

.2 Design roof system for adherence to rain screen principles, with consideration to water penetration, internal condensation, air and vapour barriers, insulation design and collateral material selection.

.3 For SNAP RIB exposed metal roof cladding ensure a minimum roof slope of 1:6 (2" in 12") is maintained.

.4 Standing seam roof systems with expansion control shall have a shear device to ensure transfer of shear loads into the supporting structure.

.5 The supporting structure shall be designed, as a minimum, for similar vertical and shear loads applied to roof cladding element.

.6 National Research Council (NRC-CNRC) Report No. B1040 Wind Uplift Resistance of Metal Roofing test results confirm that an acceptable level of wind uplift resistance can be achieved with RGC Accepted Metal Panel Systems on typical roof designs over solid decking for most British Columbia geographical locations. Refer to Appendix II for calculations for typical roof wind uplift pressure requirements for buildings located in the Province of British Columbia.

PART 2 - PRODUCTS

2.1 MATERIALS

.1 Roofing panels shall be factory formed.

.2 Manufacturer shall be a member of Good Standing with the Canadian Sheet Steel Building Institute (CSSBI) and the Roofing Contractors Association of British Columbia (RCABC).

.3 Fabricated from ASTM A 653 / A 653 M SQ (structural quality) minimum grade 33 galvanized steel with a zinc coating of Z275 galvanized as designated by ASTM A653 or ASTM A 792 / A 792M 55% Aluminium - Zinc Alloy Coated steel with an Alloy coating of AZ 150 as designated by ASTM A 792.

.4 Pan-cake #12–11 x 25 mm (1") screws or longer for insulated roof systems will be installed along the panel flange at 600 mm (24") on centre into the substructure solid wood, plywood or steel decks. 6 mm (1/4") wide x 18 mm (3/4") long holes can be placed in the panel screw flange at 600 mm (24") centres for expansion control, if required. Place screw in middle of slot unless otherwise instructed.

.5 Profile designation shall be Mercury SNAP RIB with a minimum steel core thickness of 0.61 mm (0.024").

.6 Pre-finished sheet steel, in addition to meeting the requirements of 2.1.3, shall have a 2-coat (minimum) Silicone Modified Polyester Paint or Kynar System, factory applied, cured by baking, using colours of proven durability for exterior exposure.

.7 Subject to specification Polybutylene Mastic tape caulking of suitable thickness and width will be supplied with the cladding panels for the sealing of side and end lap joints.

PART 3 - EXECUTION

3.1 STORAGE OF MATERIAL ON SITE

.1 Steel sheet roof cladding shall normally be delivered to the jobsite as required for installation, but if site storage becomes necessary, suitable storage areas shall be provided by the general contractor as close to the building site as is practical. Preferably this storage shall be under cover.

.2 When outdoor storage is unavoidable:

a) Use good quality covers, other than plastic, loosely shrouded over stacks and firmly anchored to prevent wind blow-off.

b) Tilt bundles for drainage.

c) Ventilate bundles but do not allow the entry of wind driven precipitation.

d) Block bundles off ground for effective ventilation,

e) Block bundles to prevent sagging.

f) Store away from all chemically aggressive substances (e.g. salt, cement, fertilizer), away from all materials that could contaminate the surface (e.g. diesel oil, paint, grease) and away from all traffic to avoid physical damage.

.3 Moisture can cause wet storage staining of metallic coated and pre-finished material and usually occurs as a result of:

a) Condensation from high humidity and / or temperature cycling.

b) Wet shipping conditions.

c) Wind driven rain penetration (outdoor storage).

The usual progression is from water staining to unsightly white staining (dark grey to dull black on aluminum-zinc alloy coated sheet) to red rust. On material where wet storage staining has occurred, it should be noted that, except for aesthetic considerations, a nominal amount of staining is not detrimental to the functioning of the product.

3.2 INSTALLATION

.1 All installation work shall be carried out by trained erection crews all in accordance with the fabricator’s and these specifications.

.2 Examine and obtain all necessary measurements of previously executed work which may effect the work of this Division.

.3 Exercise care in unpacking, moving, storing, handling and placing panels to prevent damage likely to impact the adequacy or appearance of the material in the finished structure.

.4 Sheet steel roof cladding shall be installed in the longest lengths possible and shall be adjusted to final position before being permanently fastened to structural supports.

.5 End laps shall be located over supports. Minimum end laps shall be:

a) 100 mm (4") for roof cladding used on roofs with a slope of 1:3 (4" in 12") or more;

b) as per fabricator’s specifications for roofs sloping less than 1:3 (4" in 12").

End laps on roofs shall be sealed with the recommended continuous sealant tape and / or caulking compounds.

.6 Subject to specification, side laps shall be sealed with continuous lengths of taped caulking.

.7 When cutting or drilling pre-finished material, care shall be exercised to ensure that cuttings do not remain to rust on exposed pre-finished surfaces. Where practical, cutting and drilling shall be conducted so that cuttings do not strike or accumulate on exposed cladding surfaces.

.8 This contractor shall remove all cuttings, grime and dirt from the cladding by dry wiping the panels as the material is erected.

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