- Q.Is there any way to remove
mildew and water stains on redwood and cedar
responds: To remove a mild case of mildew,
scrub the surface with a mild cleanser or
non-ammonia detergent. Then rinse with household
liquid bleach to kill the mildew spores. Finally,
rinse with water.
For more severe mildew infestations, scrub the
wood with a stiff bristle brush, using a solution
of one cup trisodium phosphate, one cup liquid
bleach, and one gallon of warm water. (Wear rubber
gloves!) After scrubbing, rinse with a solution of
four ounces oxalic acid crystals dissolved in one
gallon of warm water in a nonmetallic container.
Apply with a soft brush to one entire board or
defined area at a time. After the wood has dried
thoroughly, rinse with clean water. This will
remove not only mildew, but also any water stains
and extractive bleeding. It might reduce nail
stains as well, however, but nothing short of
sanding will remove nail stains entirely.
Charlie Jourdain is a finishes
specialist at the California Redwood