Cottage Q&A
QUESTIONThe aluminum screen from our cottage porch is five years old and has developed a series of small holes. Why?
ANSWER
Organic debris, such as bug guts or tree sap, if left on mesh over time, can prevent the screen from drying and lead to corrosion, according to a Canadian materials scientist, who, oddly, wished to remain anonymous. However, Alan Gray with Alabama-based Phifer Wire Products (the world's largest producer of aluminum and fibreglass insect screening) doubts that dead bugs were the problem.
"If the integrity of the coating on aluminum screening is breached," he says, "then open air gets to the aluminum and it will eventually just corrode until it basically dissolves." Contaminants that can breach that coating include acid rain, deck stains and washes, roofing treatment, and exterior vinyl cleaners. Pinning down the exact cause is tricky, he says, because no one knows exactly what kinds of pollutants waft by on the wind. But in many cases, the culprit is cleaning solutions, particularly deck wash. "Those types of cleaners contain harsh ingredients, so you must protect other materials from splashes," Gray says.
When you replace the screen, you might consider using a fibreglass mesh. It has better resistance to chemical contamination overall and is widely available at a comparable price.
* Published in the April/May 2006 issue of Cottage Life
