Prepainted galvanized steel sheet is a cost-effective and durable product. In many applications, the correct selection of paint systems (pretreatment, primer and finish) can make the service life of painted galvanized steel roof and walls reach 20 years or even longer. However, to achieve such a long service life, manufacturers of prepainted galvanized steel sheets must also consider many other issues, including the nature of the service environment, the thickness and condition of galvanized steel sheet, color coated coil coating process, panel design and roll forming process. For decades, prepainted galvanized steel sheet has been successfully used in roofs and walls under various climatic conditions.
EAST STEEL, as one of the most professional pre painted steel coil suppliers, provides various color coated steel coils made by different techniques.
Once the prepainted galvanized steel sheet arrives at the construction site, improper storage and treatment, architectural design, installation and maintenance will affect its service life.
In order to prevent the corrosion of the PPGI colour coated sheet, the removed panels must be stored in the building or wrapped with paper under a tarpaulin to keep dry. In addition, the completed building must be designed to allow all rainwater and melted snow to flow away, rather than collecting and contacting metal. If the application involves the use of fasteners that penetrate the panel, the fasteners need to be selected to match the life of the pre-coated panel. Today, the heads of screws/fasteners have an organic coating to provide corrosion protection and provide a color matching the roof/wall cladding.
During the installation process, it is important that the shoes or boots worn by workers are not allowed to embed small stones, steel drills and so on into the sole. These materials will scratch the paint and leave areas prone to corrosion. In addition, all small holes or chips (referred to as "chips") during fastening and trimming operations shall be removed from the roof immediately. The steel in the chips will corrode and leave objectionable rust discolouration, especially when the paint color is a light tone. Many times, this discolouration is considered to be the actual premature degradation of prepainted galvanized steel sheets. In addition to aesthetic issues, building owners also need to be sure that the building will not fail prematurely.
Simple maintenance of prepainted galvanized steel sheets on buildings includes washing with water from time to time. This is usually not necessary for installations where panels experience rainfall (such as roofs). However, in protected exposed areas, such as soffits and wall sections under eaves, cleaning every six months is helpful to remove corrosive salts and debris from the panel surface. Cleaning must be carried out carefully and only non-abrasive cleaners and soft-bristled brushes or cloth can be used to avoid scratching the surface. Any cleaning should first "test clean" a small surface area where there is no bold exposure to ensure satisfactory results.