How to Fix a Steel Roof

Modern surface coatings have dramatically improved the life potential of steel roofing. ZINCALUME® & COLORBOND®/ZINCALUME® finishes have virtually replaced galvanized steel in Australia.

There are four basic roof profiles which apart from appearance, suit different tasks.

Corrugated:
CUSTOM ORB ? Roof pitch over 5 

Corrugated for curving:
CUSTOM BLUE ORB ? Roof pitch over 5 

(Wide pan) Trapezoidal:
TRIMDEK HI-TEN ? Roof pitch over 3 

(Close pitched)Trapezoidal:
SPANDEK HI-TEN 700 ? Roof pitch over 5 

Secret-fixed or fastened with clips under the decking:
Wide rib
KLIP-LOK HI-TEN ? Roof pitch over 1 

Measure the length of the roof and divide it by the cover width of the sheet eg: roof length 10 metres or 10,000 mm divided by the cover width of CUSTOM ORB which is 762mm = 13 sheets.

There will be a little under the total width but this will be covered by the barge capping or flashings.

The sheet should be long enough to reach from the apex of the roof to about 50 millimetres beyond the fascia board to ensure that the rainwater runs into the gutter.

Bundles of roofing must not be placed directly on the ground. They must be placed high enough to avoid water from entering between the sheets. If considerable time is likely to elapse before installation the bundles should be provided with cover.

The fasteners must provide a life potential appropriate to the roofing. Be certain that they conform to Australian Standard 3566 Amendment 1-1990 Class 3. Otherwise the fasteners will very likely corrode early in the life of the rest of the roof. The size of the fasteners must be as recommended by the manufacturer for the particular roof profile in question.

Measure the roof to check that it is a true rectangle. When loading the roof with the sheets place them all so that the overlap edge is nearest the end where you will start laying them. They should lap away from the direction of prevailing weather.

You can pass them up to the roof as you need them but regardless of how you do it, have them all the same way around AND WEAR GLOVES.

If the roof has a pitch of less than 25 degrees the pan or valley at the top end of the sheets must be turned up and if less than 5 degrees, turned down at the eaves also, using the correct tools.

This sheet MUST be fixed correctly and is is worthwhile spending time on this detail. The first sheet MUST be fixed square to the fascia and have an approximate 50 millimetre overhang into the gutter. If it isn?t square it will cause the sheets to have uneven ends at the eaves and tend to "fan" causing continual problems during installation. Fasten this sheet placing the fasteners according to the manufacturer?s instructions but leaving out those on the edge where the next sheet is to lap.

NEXT: Position the second sheet so that it overlaps the edge of the first sheet ensuring that the 50 millimetre overhang at the eave is maintained. Clamp the lap at either end with a vice-grip or similar. Fasten this sheet leaving the side lap fasteners until last. Lightly mark the line of the purlins to be sure the screwline is straight and that you don?t miss them. Check the measurements periodically to ensure that the sheets aren?t "fanning" as installation proceeds.

While screws can be put in by means of a roof punch and some type of screwdriver, it is much quicker and easier to acquire an electric screwgun or drill attachment to allow you to use self-drilling self-tapping screws. Roofing nails have virtually been superceded by screws in Australia and if used, should have spiral shanks.

ZINCALUME® & COLORBOND® roofing acessories cannot be soldered. The appropriate sealing material is neutral cure silicone rubber sealant used in conjuction with aluminium blind ("Pop") rivets or steel fasteners having a very heavy zinc or equivalent coating.

The job isn?t finished until the roof has been swept clear of debris such as rivet stems, drill swarf and any other metal which could rust and spoil the appearance of the roof.

For more detailed information, the manufacturer?s literature and recommendations should be read.