Interior Walls showing unusual black streaks

Originally Posted By: kayshav dattatri
This post was automatically imported from our archived forum.

Our 20+ year old house has started showing a weird symptom in the last 3 weeks. I hope you experts can guide me on this

Some of the interior wall (that interface with the exterior) surfaces have developed some light black streaks. These streaks are not irregular. They run from ceiling to floor along every wall stud. I can clearly see where the wall studs are -- every darkish line on the wall lines perfectly with a stud. Further, I can also pin point the nails that attach the sheetrock to the wall studs. So, if I stand in front of the family room wall, I can see parallel streaks of light black outlines about 2" wide, one every 16 inches (the studs are 16" apart) and I can clearly identify the nails in the sheetrock.

This is not seen in walls that do not interface with the outside; i.e., walls which do not have an exterior face.


a. What could be causing this problem? Moisture, termites?

b. How do I go about getting to the root cause and fixing it?

Some details about the house:

- It is a single story house with an uninsulated crawl space and an insulated attic. The crawl space remains wet (not flooded) most of the winter/spring months.

- Gutters are maintained well and water does not accumulate around the house.

- Exterior walls are insulated with fiber glass



Originally Posted By: jhagarty
This post was automatically imported from our archived forum.

What you are describing is known as “Ghosting”

Joseph Hagarty

HouseMaster / Main Line, PA

Phone: 610-399-9864
Fax : 610-399-9865

HouseMaster. Home inspections. Done right.

Originally Posted By: phinsperger
This post was automatically imported from our archived forum.

This is being disscussed at


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