Mold found under wall paper

[jennalc1]

View attachment ImageUploadedByHome Repair1429988422.211699.jpg

We bought a house a week ago and when ripping down wall paper, we found mold. It is on an exterior wall. The wall is stone or plaster.

Help! Can we spray it with bleach and then seal it and repaint?

Does it look like black mold? Or another kind?

 

[chrisn]

Be best to have it professionally tested

 

[DFBonnett]

I've seen mold like that when a humidifier was run heavily for whatever reason. If the wall doesn't feel damp, I'd wash all paste off vigorously, allow to dry thoroughly, sand lightly, apply a quality stain suppressing oil based primer such as Cover Stain, then top coat with a quality acrylic. Keep an eye on it. If you see more mildew the problem is exterior related and will require attention.