11th Street was renumbered in the late 19th century, possibly around 1890. Thus any citations to "446 Eleventh Street" prior to the renumbering will refer to another building, and we have not yet determined exactly when the renumbering occurred.
The renumbering was certainly complete by 1897. Thus we can try searching for the address in the online 1897 Lain's Brooklyn Directory, to see if we might find the name of the resident at the time. Unaccountably, the address does not appear in the 1897 Lain's.
An address search in the Brooklyn Daily Eagle yields just one citation, a "Situation Wanted" advertisement from 1900:
Had the "respectable young girl" been currently employed at 446 11th Street, she probably would have specified "call at present employer's" in her advertisement, since it would have made it easier for prospective employers to obtain references. Thus it is likely that the girl was presently at liberty, and that 446 11th Street was her home.
Since there is no 1897 Lain's citation, but there is a 1900 Eagle citation, one might conclude that this house was built between 1897 and 1900. But 446 11th Street is probably a good deal older than that.
The reason involves what were called the "Fire Limits" of the city, or the building codes that specified whether a structure could be made of less expensive wood, or must be made of more expensive brick. The question of whether to extend the "Fire Limits" was constant throughout late 19th-c. Brooklyn:
Discussions concerning whether and where to extend the Fire Limits were contentious, and have an eerie familiarity to those who follow development issues in present-day Brooklyn. One speaker, no doubt a builder of wood frame dwellings, argued against extension, claiming that the Fire Limits constrained business; that the Fire Limits constrained growth; that wooden houses provided necessary housing for workers; and even that brick buildings were more susceptible to fire:
Brooklyn Daily Eagle, February 14, 1889, p. 1 ("Brick or Wood?")
One of the few arguments missing here is that laws mandating brick dwellings are "elitist"!
The article concludes on another note highly familiar to those who have observed local civic organizations at work: after much argument, the question was deferred and the meeting was adjourned.
The Eagle indicates that in 1890, the Fire Limit in the 22nd Ward, which included Park Slope, was extended southward from its boundary at the time, the midline between 13th and 14th Streets:
Thus in 1890, 446 11th Street, a wood-frame house, was already inside the Fire Limits. We must therefore conclude that the building, and its neighbors in 11th Street, all predate 1890, since their wood frame construction would not have been permitted once the Fire Limits included their block. If we could determine when the Fire Limits were earlier enlarged to include 11th Street, we could further pinpoint the age of these houses.
It is quite possible that 446 11th Street, or at least its eastward neighbors with the single-story bay windows, could be as old as the 1870s. The single-story bay window seems to have become popular in that decade, as evidenced by these somewhat similar houses from 13th Street that we have definitively dated to 1870 based on Eagle citations:
Many of these very old wood frame houses in the South Slope have lost much of their original character. With a great deal of effort (and money), however, some homeowners have been restoring some of the original grace to these neglected dwellings that once sheltered clerks, tradesmen, and "respectable young girls".