Roofing Material Modern Marketoffers a fairly wide selection of roofing materials. The most popular are relatively inexpensive and technologically advanced coatings: steel (galvanized and with a polymer coating), metal, bitumen and cement-sand tiles. At the same time, the demand for elite materials is growing: roofing ceramics, non-ferrous metals, natural slate, wood and straw. It is necessary to decide on the choice at the stage of the preliminary design of the house. The type of roof affects not only the architectural appearance of the building and the design solution of the rafter part of the roof, but also the overall estimate. The costs of materials and work can reach 20-30% of the cost of construction.
Strong as steel
Black metal is used for coatingpitched roofs almost since the moment when it became technologically possible to roll steel into a thin sheet. A serious drawback of such a roof is the high rate of oxidation of the material under the influence of atmospheric oxygen (corrosion) and, as a consequence, the relatively rapid destruction of the coating. When purchasing metal tiles, preference should be given to reputable manufacturers who provide a guarantee for their products for at least 10 years. The situation has changed thanks to galvanizing. In factory conditions, a zinc layer 20 μm thick is applied to the steel sheet using a hot method. The oxidation rate of non-ferrous metal is 0.04 μm per year. It is easy to calculate that even in unfavorable conditions the coating can last 20 years. Another advantage of zinc is its ability to spread. Thanks to this property, edges cut with scissors and small scratches soon heal. However, galvanized roofing looks rather dull. In addition, zinc weathers and is washed out over time. Decorativeness and additional protection of galvanized steel are provided by a polymer coating. Modern roofing material has a multilayer structure. The zinc layer (its thickness has decreased to 14 microns), treated by chemical etching (passivation), acquires adhesive properties. A primer is applied to it, which, in turn, is covered with a decorative weather-resistant polymer (from the front side) and acrylic varnish (from the inside). Steel can have a protective and decorative coating of different types. The choice depends on the degree of aggressiveness of the environment (a quiet rural area, a sea coast or proximity to a congested highway), climatic conditions and the financial capabilities of the owners of the house.
