I just spent an hour reading about sentences like this:
I am sat here.
She was stood there.
In this question people tackle whether it's correct usage or not, which is not the point of my question.
Few people would argue that "I am done here" is non-standard English. 'Done', the past participle of 'do', is listed in the Oxford Dictionary of English as an adjective, so it's easy to see why "I am done here" is standard.
The verbs "sat" and "stood" are both past participles, but they are not listed as adjectives in the same dictionary. Are they acting as adjectives in the two example sentences?