Prodek® Roofing & Wall Cladding

Material Specifications

Design Considerations

The minimum recommended roof pitch for Prodek is one degree (1 in 60). With a one degree fall, ensure that building settlement or the warping of timber structural sections does not cause ‘ponding’ on the surface of the roof. The 650mm coverage of Prodek provides easy handling and installation. Prodek roofing is subject to thermal expansion, particularly on darker colours. The maximum length before an expansion joint is required is 24 metres for lighter colours, and 16 metres for darker colours.

Compliance

The Wind Capacity Tables are based on testing in accordance with AS1562.1-1992 and AS4040.0, 1 & 2-1992. Span tables have been developed by determining wind pressures in accordance with AS4055-2012 for domestic applications and AS/NZS 1170.2:2011 for all other applications. Capacity tables are in limit state format.

Spans

Spans are determined by wind speeds for non-cyclonic areas. For domestic applications, the pressures and spans are based on an eaves height not exceeding 6m, a roof pitch no greater than 35? and a total roof height of maximum 8.5m. For commercial and industrial applications, span tables are based on a maximum overall height of ten metres and a 500 year design return period.

Roofing calculations are based on Cpe=-0.9 and Cpi=0.2, walling is based on Cpe=-0.65 and Cpi=0.2. A local pressure factor, Kl=2.0 has been used for all roofing spans for both strength and serviceability limit states. Roof spans take into consideration loads incidental to maintenance.

All pressures have been determined assuming wind loading in any direction but which is not affected by topography. The following shielding factors, Ms, have been used for each of the terrain categories: Category 3 = 0.85, Category 2.5 = 0.95, and Category 2 = 1.

Domestic carport and verandah spans only apply to structures not enclosed by peripheral walls. Spans are based on Cpn=-0.9 and Kl=1.5 applied over the entire span, and are suitable for all span types. Loads on supporting purlins may limit these spans.

Stratco can provide additional engineering advice if any design parameters vary from those above.

Maximum Recommended Spans

Roofing: Spans are limited based on typical maintenance foot traffic.
Walling: Spans are based on N1 (W28) wind loading.

Domestic Carport / Patio Spans

Prodek Spans

Values are for use with steel supports with a minimum thickness of 0.95mm, G550.

Wind Load Conversion

For domestic applications use the appropriate wind classification for the area. To read the span tables for commercial and industrial applications, select the region and category for the area, then convert it to a wind classification using the table below.

Wind Capacities

The values are for use with steel supports with a minimum thickness of 0.95mm, G550.

Water Carrying Capacity

The peak rainfall intensities shown represent a 100 year average recurrence interval (ARI) for a five minute rainfall duration. If roof penetrations exist, the total roof run will generally be greater than the distance from ridge to eaves at the location the penetration interferes with the runoff. Contact Stratco if further advice is required.

Fixing Recommendations

Lay Prodek sheets into the prevailing wind. They should sit neatly on the preceding sheet, and be fixed at the recommended support spacings. Avoid ‘stretching’ the width of the sheet when installing, as this could allow wind and rain to enter. Flashing turn downs into the pan of Prodek should always be notched around the rib for maximum weather tightness. For spans between 1200mm and 3600mm, side lap fasteners are recommended for use at mid-span. For spans beyond 3600mm use two evenly spaced fasteners between supports to secure the side lap. Use either 8 x 12mm self drill stitching screws or 4.8mm sealed blind rivets. On roofing, at the end of the sheets, turn the pans up at the roof crest and down into the gutter using a turn up/down tool.

Roof Laying Procedure

Wall Laying Procedure

Fastener Selection

If fixing over an insulation blanket the next screw length to that indicated may be required with minimum 25mm timber embedment to be maintained.

Walking on Prodek

When walking on Prodek roofing, it is recommended you walk over the purlins to avoid damage. Wear flat, rubber soled shoes and walk flat footed in the sheet pans only. For carport and verandah applications, crawl boards should be used to avoid damage during installation and maintenance.

Using Prodek

Stratco Prodek will have a long, useful life if used according to Stratco specifications. While roofing materials in outer urban and rural areas may have a life-span in excess of 30 years, this can reduce to only a few years in coastal and industrial environments.

Zinc/al and pre-painted steel should not be used in very aggressive areas such as near swimming pools and spas. It is important that dirt, soil, compost, paving sand, or other materials which retain moisture are not placed against steel sheeting. Concrete should not be poured against zinc/al material. Check with Stratco before using in these severe environments.

Incompatible Metals

The best way of reducing corrosion is to keep incompatible metals apart. Zinc/al and pre-painted steel cannot be used with lead, copper and monel. Galvanised steel and pure zinc material can be used with zinc/al, but you must avoid water run-off from zinc/al onto galvanised material. Fixings such as rivets and self-drilling screws must be compatible with the material they are fixing.

Handling and Cutting of Prodek

For safety, wear gloves when handling Prodek. Ensure your hands or gloves are clean, especially when handling zinc/al which can mark. Use a coloured pencil for marking steel, as lead or black pencils contain graphite which promotes rusting. Prodek is best cut using tin snips, but for larger cuts it may be necessary to use a power saw with a steel cutting blade or a power nibbler. Avoid using abrasive discs as they can cause burred edges and coating damage. Where possible cut sheets on the ground, and always clean off any swarf and metal filings progressively during the installation. Dispose of off-cuts carefully.

Insulation and Sealants

The use of blanket insulation is recommended in domestic roofing to assist in temperature, condensation and sound control. When using Prodek with insulation blanket, longer fasteners may be required and greater care is necessary when installing.

When choosing a silicone sealant, ensure it is suitable for roofing and guttering use and of a non-acetic, amine free, neutral cure type. Sealants that smell of ammonia, vinegar or lemons are not usually suitable.