After seaching and reading about molds, I still not sure...
While I start removing wallpaper in my kitchen there's small area of
black stuff underneath mostly close to the cieling. Then there's one
sheet of wallpaper on the same wall was covered solid black, and the
sheet next to it was clean. the stuff looks dry to me, and there's
some white (original paint show through it), some of the stuff came
off with wall paper, and some grey material showed underneath behind
it(part of the cardboard?)
When I push that section of wall it caves in at the bottom around the
trim area. I heared that they had fix somekind of dryrot? in bathroom
floor (which is directly above kitchen. they hired a handyman who
might just replaced the vinyle flooring. They also replaced several
outside sidings board that was rotten. Also in the garage which is
attached to the kitchen, they replaced a moldy spot, but was told
there weren't anything underneath. Finally the previouse owner had
passed away, so there's littl information on what happen to it.
My parents bought this place (as part of their retirement plan) while
I go to school here in N. Cal, and it has been nothing but trouble.
I hope I don't have to replace the wall. I am not very experienced
with home improvement stuff. but I'm welling to learn to fix it
myself... I just hope it will be cheaper than what I would get if I
rent somewhere else...instead live in parent's place for "free".