Power Washing and Roof Cleaning Forum

DirtyRoofcom · Approved Exterior Cleaner

What is this?

BlueRidge · Approved Exterior Cleaner

I wish there was a better picture of the siding.

Art O · Approved Exterior Cleaner

Look like white stain

Zach Maynard · Approved Exterior Cleaner

Yeah looks like the shingles are either painted or stained white and then completely covered in funk.
Make sure if there is bare wood anywhere there that they know that is from age and bacteria growth and not from your process before you start.
The fungi is on the natural cedar, anywhere you see white circular shaped areas that make the cedar look a tad lighter is white rot fungi.

Dave O · Retired Member

Erik, let us know how the test spot turned out.

Bruce Sullivan · RIP

White rot fungi isn't as common with cedar as brown rot fungi. Would like to see a closer picture.

Jeff Wible · Approved Exterior Cleaner

I agree with the others,..looks like it was stained 30 years ago and the stain is wore off from the weather where the wood is exposed and the area in the picture is protected allowing the stain to remain. With that said, the remaining stain is still very aged and should be able to be removed with a few light applications of something like Sodium Hydroxide. Use it in a lighter than normal solution,..I'd start with like 4-6 OZ. per gallon and go from there,..remember to get the cedar underneath wet before applying and neutralize afterward.

Jeff