2021-07-22

Steel Roofing Products – Selection Guide 02

INTRODUCTION

This Technical Bulletin serves as a guide to selecting the most appropriate BlueScope product for your walling needs considering intended location and the environmental factors likely to be encountered during service. Selecting the correct product for the location will contribute to ensuring that your wall achieves a long service life. The ability of COLORBOND® preprinted steel and ZINCALUME® aluminum/ zinc/magnesium alloy coated steel with Activate® metallic coating technology to excel in the climatic conditions of Australia is the result of the advanced coating technologies applied to the base steel strip. Below is a brief description of BlueScope’s walling products.

RECOMMENDED WALLING PRODUCTS

DISTANCE FROM MARINE INFLUENCE

ZINCALUME® steel

>1km (for commercial and industrial applications)

COLORBOND® steel

>1km

COLORBOND® Metallic steel

>1km (for commercial and industrial applications) >2km (for residential applications)

COLORBOND® Ultra steel

COLORBOND® Stainless steel

>500m

>0m

Table 1: Suitable BlueScope product guide for walling in marine environment

01 PERFORMANCE OF STEEL WALLING

Like steel roofing (please refer to: https://www.bluescopelanka.com/news-single.php?id=13) the performance of steel walling can be influenced by a number of factors, including the environment, particularly its proximity to a salt marine influence. Typically, walling experiences less natural washing by rainfall when compared to roofing, which has influenced product recommendations. Table 1 serves as a GUIDE ONLY for the selection of a walling product for your location. In combination with a REGULAR 6 MONTHLY MAINTENANCE PROGRAM, this should provide optimum performance and longevity.

02 UNWASHED AREAS

 A common issue in the case of walling is in areas not naturally washed by rainfall, known as “unwashed areas”. Since walls are vertical surfaces, they can be sheltered from general rain washing, particularly towards the top of the wall, adjacent to overhanging eaves. In these regions dust and dirt, that would otherwise be washed away by rain, tends to build up. Condensation can be absorbed by the dust and dirt leading to an increase in the time that the material is in contact with sufficient moisture to initiate corrosion (i.e. time of wetness). The associated effects of these unwashed areas can be accelerated in the vicinity of a salt marine influence, when the build-up of dust and dirt includes marine salts, and/or other pollutants (e.g. industrial fall out), unwashed area corrosion is further exacerbated. The potential for corrosion to occur in unwashed areas can be reduced by regular washing with fresh clean water

03 DESIGN

 To improve the thermal efficiency of a building, modern building design often incorporates large overhanging eaves, verandas and walkways in combination with walling made with COLORBOND® steel and/or ZINCALUME® steel. It is important for a designer to recognize that the inclusion of such overhanging features will create unwashed areas. Where unwashed areas are created, selecting a suitable product (refer to Table 1) and implementing a regular maintenance regime will aid in the longevity of the walling product. Wall cladding installed with the formed profile in a horizontal orientation creates inherent unwashed areas which may hold dust and dirt. Accordingly, a more regular maintenance program than quoted may be required. Consideration also needs to be given to ensuring that the wall cladding is installed in such a way that it is not immersed in concrete, dirt, soil or other moisture retaining substances. Ensuring a free drip edge is achieved on the bottom edge of the walling so that water is allowed to drain freely away from the entire walling surface is also important. More information can be found on the above topics in the following Technical Bulletin.

04 MAINTENANCE, FASTENERS AND ACCESSORIES

 Maintenance, in the form of regular washing with clean fresh water, should be performed at 6- month intervals. To support product longevity, information should be sought on the correct choice of fasteners, accessories, and good storage and handling practice.

05 THERMAL EFFICIENCY OF STEEL WALLING

Properly insulated steel walling has inherent thermal efficiency benefits due to its low thermal mass. Thermatech® solar reflectance technology  provides further thermal efficiency benefits and is incorporated in COLORBOND® steel standard and matt finish colours (except for Night Sky®) and COLORBOND® Ultra steel standard colours. This technology is designed to reflect more of the sun’s heat on hot, sunny days. For more information on Thermatech® solar reflectance technology, as well as other notes on thermal efficiency.

 

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