I have a composite deck and rail system. It was installed a little over 1 year ago. It has developed what appear to be mold spots. I have cleaned it once with bleach. This remedied the spotting, but it has now returned with larger spots.
The manufacturer is Portico and they recommended sealing the material. I have not received a recommendation as to which sealer is appropriate for their material that will not void a warranty or that will not require continual maintenance.
I am looking for suitable sealer that will meet both of these needs.