Dull and Cloudy Finish On Aluminum Siding
Common Painting Problems
A dull or cloudy appearance on aluminum siding is not uncommon. Although aluminum siding lasts indefinitely, the factory finish on the siding is paint, and therefore susceptible to climactic conditions. The primary failure of this factory finish is chalking. This is an actual breakdown of the paint’s finish. It is caused by the sun’s ultra-violet rays, which, over time, break down the protective resins in the paint. As the resins break down, the pigment is exposed, leaving a dusty or chalky film.
You may notice stains on the brick below your siding. These are a result of rain washing the exposed pigment fibres from the siding, and depositing them on the brick below. You may also notice that when you rub your hand across your siding you are left with a dust or chalk film on your hand. These both are evidence that the factory finish on your aluminum siding has weathered, the resin is broken down, and just the pigment remains. If left long enough, all the resin and pigment will be “washed away,” leaving only a metal surface.
Fortunately the siding does not need to be replaced. It can be refurbished quite simply with paint. We cannot, however, paint directly over the chalked surface. This would result in extensive peeling, as the new coat of paint has nothing substantial to adhere to. Simply stated, paint can not stick to a dusty surface.
Your crew from Student Works Painting will prepare your siding before we apply the finish coat. Preparation will consist of a thorough wash. This is done with scrub brush and buckets, using trisodium phosphate (TSP) or a more environmentally friendly alternative on especially dirty areas. Our crew chief will ensure that all exposed pigment is removed before any paint is applied. Should any of the factory applied paint have washed off to bare aluminum, we will spot prime those areas to maximize adhesion and coverage of the finish coat.
If you are not changing colour, generally one finish coat will be sufficient. However, if previous chalking was severe, it may take two coats to achieve adequate coverage for appearance and protection. Once the work is completed, you can rest assured that the job will last. We guarantee it for three years, but suggest that because aluminum siding will not experience the moisture problems of conventional siding, it will last much longer.
**Warning: When recoating aluminum siding, do not paint it with a colour that is significantly darker than the original factory finish. You may paint with a lighter colour, but not darker. A darker colour will absorb more sunlight and become hotter than the siding originally did, and will therefore expand more in hotter temperatures. This expansion may cause the siding to buckle. This is inconvenient and expensive to repair.