What Can I Use to Clean Algae From Redwood?

Redwood is a durable material used in the construction of decks, siding and furniture. Proper cleaning of the redwood removes any debris from the surface, including algae.

Cleaning

Wolman suggests using a cleaner that contains oxalic acid as a main component. Oxalic acid is strong enough to remove any type of surface stains, including rust and algae. Rub as much algae away from the redwood as possible, scrub with the cleaner, and then rinse with fresh water.

Considerations

If the algae leave behind dark stains or marks, then you may need to scrub the surface with 150-grit sandpaper. Clean the redwood first, and after the wood dries, rub it with the sandpaper. Wipe off any sawdust clinging to the surface and, if needed, stain it with a matching stain color.

Prevention

Redwood has a tendency to turn gray when left untreated. After cleaning the surface of the redwood, apply a wood sealant or protectant. The sealant also prevents algae from clinging to the surface of the wood and leaving behind stains.

References

• Wolman: What do I use to clean cedar or redwood?
• Decorate-Redecorate: Outdoor Furniture: Tips for Cleaning Furniture