How to Install Corrugated Iron Roof Sheets

Fastening sheets to supports

Our products are pierce-fixed to steel or timber supports.

You can place screws through the crests or in the valleys. To maximise watertightness, always place roof screws through the crests. For walling, you may use either crest or valley-fixing.

Always drive the screws perpendicular to the sheeting, and in the centre of the corrugation or rib.

See illustrations below:





Side-laps

The product must be overlapped at the sides not less than 1.5 corrugations. It is generally considered good practice to use fasteners along side-laps however, when cladding is supported as indicated in maximum support spacings, side-lap fasteners are not usually needed for strength.

Ends of sheets

It is usual to allow roof sheets to overlap into gutters by about 50 mm. The valleys of sheets should be turned-down at lower ends, and turned-up at upper ends.

Laying procedure

For maximum weather-tightness, start laying sheets from the end of the building that will be in the lee of the worst-anticipated or prevailing weather.

Lay sheets toward prevailing weather. Also, it is much easier and safer to turn sheets on the ground than up on the roof.

Before lifting sheets on to the roof, check that they are the correct way up and the overlapping side is towards the edge of the roof from which installation will start.

Metal and Timber Compatibility

Lead, copper, bare steel and green or some chemically-treated timber are not compatible with this product; thus don't allow any contact of the product with those materials, nor discharge of rainwater from them onto the product. If there are any doubts about the compatibility of other products being used please contact us

Storage and Handling

Our product may be sharp and heavy. It is recommended that heavy-duty cut resistant gloves and appropriate manual handling techniques or a lifting plan be used when handling material. Keep the product dry and clear of the ground. If stacked or bundled product becomes wet, separate it, wipe it with a clean cloth to dry thoroughly.

Handle materials carefully to avoid damage: don't drag materials over rough surfaces or each other; don't drag tools over material; protect from swarf.

Swarf

Sweep all metallic swarf and other debris from roof areas and gutters at the end of each day and at the completion of the installation. Failure to do so can lead to surface staining when the metal particles rust.

 

Our product has a corrugated profile, equally at home with traditional and contemporary design. It is a wide, strong and lightweight profile that can be quickly and easily installed. Add up these features and you have a steel roof or wall cladding that simply offers outstanding value.

The gently curving shape of the classic Australian roof is reflected in some of today’s most adventurous and dramatic designs.

Simple, low-cost fixing

Corrugated sheets can be fixed with hex head screws ensuring fast and simple installation with the recommended side lap (one and a half corrugations).

 

Colours

Our products are available in an attractive range of colours in colorbond® factory prepainted

steel and in unpainted zincalume® aluminium/zinc/magnesium alloy coated steel. Standard colorbond® steel is available in a select range of contemporary colours suitable for all building projects.

Colorbond® steel with Thermatech® Technology

Thermatech® solar reflectance technology is now included in the standard COLORBOND ® steel palette. COLORBOND ® steel with Thermatech® technology reflects more of the sun’s heat, allowing both roofs and buildings stay cooler in summer. In moderate to hot climates, compared to roofing materials of similar colour with low solar reflectance, COLORBOND ® steel with Thermatech® can reduce annual cooling and energy consumption by up to 20%.

 

Minimum roof pitch

A special anti-capillary forming in the side lap allow you to use custom orb (or Custom Blue Orb used on curved surfaces) for roof pitches as low as 5 degrees (1 in 12).

 

Sheet lengths

Sheet lengths of up to 24m can be used before an expansion joint is required for roof applications.

 

Lengths

Sheets are supplied custom cut.

 

Corrugated roofing Maximum Support Spacing data:

 

Turning-up our products

With pliers, multi-grips or a shifting spanner closed down to approximately 2mm, grip the valley corrugations 20mm in from the end of the sheet and turn up as far as possible. Be careful not to tear the sheet.

 

Rain Fall Capacities Data:

 

Masses Corrugated Roofing

(Steel)

(mm) BMT

Kg/m

Kg/m2

m2 /t

Zincalume

0.42

3.26

4.28

234

Colourbond

0.42

3.32

4.35

230

Zincalume

0.48

3.70

4.86

206

Colourbond

0.48

3.76

4.93

203

Walking on roofs

When walking along the length of corrugated roof, walk only in the pans. When walking across the width of the sheeting, walk over or close to the roofing supports. Generally, keep your weight evenly distributed over the soles of both feet to avoid concentrating your weight on either heels or toes. Always wear smooth soft-soled shoes; avoid ribbed soles that pick up and hold small stones, swarf and other objects.

 

Sealed joints

For sealed joints use screws or rivets and neutral-cure silicone sealant branded as suitable for use with galvanised or zincalume® steel.

 

Laying procedure

For maximum weather-tightness, start laying sheets from the end of the building that will be in the lee of the worst anticipated or prevailing weather. Lay sheets toward prevailing weather. Also, it is much easier

and safer to turn sheets on the ground than up on the roof. Before lifting sheets on to the roof, check that they are the correct way up and the overlapping side is towards the edge of the roof from which installation will start. Place bundles of sheets over or near firm supports, not at mid span of roof members.

 

Fasteners

All fastening screws must conform to AS3566 – class3. They are to be hexagon headed and must be used with sealing washers for both roofing and walling applications. For connecting to purlins and top hats use the following:

 

 

Cutting

Our corrugated products can be very easily cut, when required, by using a power saw with a steel cutting blade or a power nibbler. For smaller areas, tin snips will be fine. Avoid using abrasive discs as these can cause burred edges and coating damage.

Condensation

The underside of metal deck roofs provide conditions under which condensation of water vapour will occur. Please consider the following:

Proprietary metal-strip roofing does not need the support of a (structural) deck, as this is usually omitted for economy. Condensation will then form under the roof sheeting and drip from it in a manner of frost-drip familiar with corrugated galvanised steel roofs. Absorbent treatments, applied to the underside of the sheeting, and glasswool (bulk) thermal insulation material placed beneath the sheeting are of value in reducing the likelihood of condensed water falling. It is commonly thought that condensation under metal roofing can be eliminated by liberal ventilation of the roof space. That is not so, although some relief is possible that way.

On clear nights, roofs become several degrees colder than the adjacent atmospheric air, so that air entering the roof space may be cooled by contact with the roof. The depression in temperature can be sufficient to cause condensation of water from the inflowing air. In other words, uninsulated metal roofs, whether foil laminated or not, are more likely to suffer from condensation than an insulated roof system. See illustration below:

In conventional buildings, particularly those heated in winter, condensation of water vapour will often occur to such an extent that ceilings will become stained.

A vapour barrier underneath the blanket insulation is essential to prevent moisture from inside the building penetrating and wetting the blanket insulation.

In very cold climates and where sufficient air space exists between the roof sheeting and the blanket insulation, condensation is likely to drip on to it. In such cases, the insulation blanket should be covered with a second vapour barrier such as reflective foil sarking or plastic sheeting. For more temperate climates where the moisture will evaporate during the day and the roof space is adequately ventilated, the upper vapour barrier may not be necessary,

In buildings without ceilings, such as factories, condensed water may fall on the machinery or stock in the space below.

Footnote:

**Non-cyclonic areas**

The above information is suitable for use only in areas where a tropical cyclone is unlikely to occur as defined in AS 1170.2:2002.

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