Trex flooring should never be pressure washed with high pressure. The staining is caused by mold and mildew. It is best to approach the stain like ‘pest control’ rather than a cleaning. In doing so you can be guaranteed longevity in the cleaning instead of merely blowing live mold spores around the property. After an anti-microbial detergent is applied and the mold is dead the decking can be rinsed with a low-pressure, high volume water.
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