Is there any evidence of prior old stain? Just below the soffit would tell the tale. And/or if you or the homeowner are planning on staining shortly… If so to either scenario, percarb + surfactant at say 6 oz./gal., fairly low pressure wash, and then a light acid, say 4 oz./gal. of oxalic or 6 oz./gal. of citric.
Otherwise, a bleach bath at no more than 2% sodium hypochlorite with a bit of soap and surfactant, followed by careful P’washing. Older cedar firs easily.
Sodium hydroxide is overkill and talk about firring!
Not sure what you mean by “leaving money on the table” with cedar. If you would care to explain, or call me.
I meant giving the jobs away and not doing them myself. For the last few years cedar restoration was not on my service list and I was giving the jobs to other contractors. I’m ready and equipt to start adding the service now.
Did you ever find out the answer to this? I am in the same situation now. I’m tired of passing up the Cedar jobs. I had a customer call me with a huge 2 story cedar house and I don’t wanna have to rent a man lift or anything so I’m trying to find out if I can just use my soft wash nozzles and downstream from the ground.