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Advantages | Questions & Answers | General Information
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Select COLORBOND or ZINCALUME steel for your gutters, products which will provide equal service to that of the roofing material. BHP Steel no longer recommends the use of galvanized rainwater products.

Lead Flashing

Lead flashing should not be used with ZINCALUME steel. Soft zinc or aluminium should be used instead.


Neutral cure silicone rubber sealants are the only sealants recommended for use with COLORBOND and ZINCALUME steel. The advantages of neutral cure sealants are:

  • They provide good adhesion

  • They do not require a primer except in extreme service conditions

  • They resist extremes of both heat and cold while retaining good flexibility

  • They provide very high resistance to the damaging effects of ultra-violet rays and do not have acidic additions which may adversely affect steel.

This gives long life compatible with the performance of COLORBOND steel. Sealants should be applied to avoid exposure to UV rays (i.e. sandwiched in the lap), and so they don't create water run-off and dirt tracks down a roof or facade.

Swarf Removal

Don't forget to clean up each day. Swarf particles and other metal scraps, such as pop rivet stems and fasteners, if left on a COLORBOND steel surface, will cause rust stains which detract from the finished appearance. Swarf should be swept or hosed from the job at least at the end of each day. Maximum care should be taken when attempting to detach swarf which has become stuck; this can be done, but no action which is likely to remove the paint or metal coatings should be attempted. For critical applications, inspection of the job should be made after two weeks when rain or condensation will have caused any remaining swarf to rust, and will highlight affected areas.

Cut Edge Protection

The feature of cut edge protection is one that has sold ZINCALUME steel for years. The secret is in the metallic coating which performs in two ways:

  • as a barrier, when the steel base is completely enclosed by the coating

  • as a sacrificial coating at edges when the barrier is broken by slitting, cropping, piercing or scratching.

COLORBOND and ZINCALUME steel will not corrode at its cut edges. The zinc in the coating is preferentially sacrificed to protect the steel exposed by slitting, cropping, piercing or scratching. Zinc compounds tend to build up at coating interruptions slowing the rate at which the surrounding coating is consumed during the protection of damaged areas. This effect is referred to as "self-healing".

Brick Cleaning

Brick cleaning fluids are very strong acids. They are used to clean mortar from the face of recently laid brickwork. If this acid is allowed to flow across sheeting and into gutters early failure of the paint and corrosion of the metal can occur.

Where the second storey of a brick veneer dwelling sits above a roof section of the first storey, there is a danger that the COLORBOND steel roof or gutter can be damaged during brick cleaning. Builders should ensure that brickwork in these locations is cleaned before roof and gutter installation.


To get the best possible performance from a COLORBOND steel roof it is vital you treat it with care. Areas not washed by rainwater need regular hosing. These include soffits, wall cladding under eaves, garage doors and the underside of eave gutters. Washing should be done at least every six months and more frequently in coastal areas and areas where high levels of industrial fallout occur.

Touch Up

Have you ever noticed how an otherwise professional job can be ruined by clumsy attempts to touch up minor damage such as scratches? The use of spray cans results in not only coverage of the scratch but also of a considerable area surrounding it. The problem is not immediately obvious. But overspray paint weathers at a different rate to the oven dried paint on COLORBOND steel and, eventually, you will be left with an unsightly blemish on the sheet. Our recommendation is not to touch up. Minor scratching will not affect the life of the sheet and is rarely obvious to a casual observer. Should damage be substantial the sheet should be replaced.


As with all building products, the appearance of COLORBOND steel may weather in time. When this occurs the appearance may be restored by repainting. The high quality paints films used to coat COLORBOND steel are an excellent base for repainting. For information regarding repainting, please contact your supplier.

Most of today's slate quarried in North Wales and Spain consists of large boulders which are blasted or hewn out of the mountainside and brought to the surface.

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