Shingles turned black? Check moisture first

Q. Our recently bought house as many wood shingles which have turned black. How can we bring them back to their natural shade? Andrew L. Barber Athens, Ohio

A. Cedar shingle walls will weather to light- and dark-brown shades, and sometimes to silver gray in salt air.

Black discolorations on shingles may indicate inner-wall moisture that has turned into mildew or fungus. The lack of a moisture barrier may be permitting the humidity to exit through the walls.

Unless the source of the moisture is cut off, exterior treatment alone may not provide a permanent improvement.

You can apply an oil-base enamel paint to the inside walls, which may provide the needed moisture barrier. Once the moisture problem is licked, you can go ahead and bleach the outside shingles.

Household bleach mixed with water should remove the black.