I moved in this 1920s built house at the end of last year. The floor joists look brittle. Recently i found some cracks on the floor joists ( I am sure they were there for a long time), some are long, some are short, some are visible, some are not that visible. And there is a pretty small area on one joist that has some termite damage ( I guess it's termite, but not sure, the area is about 2"x10"). As a result, my first floor produces some squeaky, funny noise when we walk on it, and it is not very leveled. My questions are:

1) are these problems (joist cracks, little termite damaged area) common in the house this old?
2) if i want to put some sister joists on, who should I call? a floor specialist, a carpenter or some one else?
3) how can i tell the termite is under control, if there is any.

Responses are appreciated

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