You chose composite decking partly because it was supposed to be easier to maintain than wood. But if your composite deck is in a shaded yard in central Pennsylvania, you have probably noticed that it does not stay as clean as you expected. Nothing is wrong with the material. The environment is the problem.
What Shade Does to a Composite Deck Surface
Sunlight is a natural suppressor of biological growth. UV radiation kills algae and inhibits the organisms that cause surface staining on exterior materials. Composite decking in full or partial sun benefits from this natural suppression.
Composite decking in shade gets none of it. Shaded deck surfaces stay cooler and retain moisture longer after rain events. They receive little to no UV radiation to suppress biological growth. The conditions on a heavily shaded composite deck are essentially ideal for algae and organic film to establish and spread.
The Role of Organic Debris
Shaded yards in central Pennsylvania produce a constant supply of organic material that lands on composite deck surfaces.
This material breaks down on the composite surface, releasing tannins that stain the composite. A heavily shaded composite deck under a mature tree canopy can develop significant tannin staining within a single growing season.
Moisture Retention and Biological Growth
Shaded composite surfaces retain moisture significantly longer than sun-exposed surfaces after rain events. That extended moisture creates the conditions algae and other biological growth need to establish on the composite surface.
What This Means for Your Cleaning Schedule
For composite decks in heavily shaded yards in Northumberland County, the standard once-a-year cleaning recommendation may not be sufficient. Twice-yearly cleaning is a more appropriate schedule for shaded composite decks with significant tree coverage above.
For composite deck cleaning in Northumberland, PA, that accounts for the specific conditions of shaded Pennsylvania yards, Kleen-N-Brite uses composite-safe solutions and appropriate pressure levels.
