Metal siding is one of the most commonly used material for the exterior shell of an industrial building because of its durability and long life cycle. Most exterior applications are either steel or aluminum and these are generally factory ﬁnished to provide a 25 or 30 year life span before requiring steel or aluminum siding painting. The inside walls of a factory are most usually painted to enhance the appearance and working environment for employees.
As durable as these exterior siding materials are, they still deteriorate in our harsh climate and especially with exposure to the sun’s UV rays. This is often noticeable when walking around the building – the south elevation is often visibly more weathered and faded than the north side.
Steel siding, because it is a more rigid material, is generally less prone to denting and warping than aluminum, but is of course more vulnerable to rusting. Aluminum also oxidizes – in fact, the anodizing process itself is an electro-chemical means of creating an enhanced aluminum oxide (“aluminum rust”) that protects the aluminum underneath.
The possible pitfalls in metal siding painting are several, but can be summarized in a few words: adhesion, protection, and durability.
Because metal siding painting is extremely smooth when it comes out of the factory, it is imperative that a correct coating system is selected when it is time to paint. This varies with the type of factory ﬁnish (anodizing, galvanizing, ﬂuorocarbon, etc.) – correct preparation minimally requires pressure washing and may need further processes and proper priming to ensure long-term adhesion to metal that will expand and contract in the wild swings of heat and cold typical of our climate.
Where rusting has begun on steel siding, there is the added challenge of ensuring this is properly treated to prevent it from re-occurring. This becomes doubly important when siding is used to form a sloped roof (such as often seen on strip malls) that will be subjected to snow loads and water accumulation.
Nature has a way of making everything deteriorate over time; how quickly or slowly is determined by the durability of the coating. How long will it protect the substrate underneath? And how long will it maintain a good appearance? As siding (particularly aluminum siding painting) is often painted when the original ﬁnish has deteriorated to a point that it is unsightly, one wants to make sure the newly painted surface will maintain its appearance for years to come.
While there is no “one-size-ﬁts-all” when it comes to painting metal or aluminum siding, professional aluminum siding painting contractors can help make the best choice of a coating system and avoid costly mistakes.