Black Staining On Roof Sheathing

These are commonly seen underneath roof vents plumbing stacks vent hoods and around chimneys.

Black staining on roof sheathing.

The leak was fixed. Across the entire eastern half of the country roof shingles tend to grow a species of algae called gloeocapsa magma. However i was in the attic the other day and noticed the underside of the roof sheathing plywood at the old leak area has some black staining where the plywood got wet from the leak. Below is a more typical example of mold growth.

Natural wood is expensive. It was a result of bad flashing at the chimney pentration. It appears in streaks or patches of slime that can be anywhere from blue green to dark black. Mold usually causes a musty odor and may cause staining that may be black brown gray white yellow or green.

I had a roof leak a year or more ago. Mold can form but often it. If these isolated spots are seen away from these roof penetrations then the roof may be damaged and leaking. The original skip sheathing has much less growth.

Builders forever looking to save a few bucks began turning toward plywood roof sheathing. After several years of this there may be dark rings around protruding roofing nails and larger dark spots or areas on the roof sheathing and or exterior gable walls. If your roof is older or in bad shape and needs replaced anyway you may want to invest in these copper infused shingles. It s been over a year since the leak was fixed and the stain is not going away on it s own.

Roof algae rarely poses a threat to the health of the roof. It may be difficult to remove the mold stains from sheathing but you can kill. When moisture condenses on plywood roof sheathing repeatedly or continuously the wood will turn black. Green or black algae stains.

Note the heavy staining and growth on the plywood. Here is a diagnostic guide to types of stains and staining materials found on roof surfaces black red green brown or other coloured stains on asphalt roof shingles or on other roofing materials need first an accurate diagnosis of the stain cause and then proper steps to remove the stain or to prevent future staining on roof shingles surfaces. The following picture is of a long standing moisture condition in an attic where much of the roof sheathing has turned black.