The composers of this song, L. Russell Brown autobiography THE QUINTESSENTIAL HITMAN. and Irwin Levine, were thinking of the song Up on the Roof and they wanted to write a song with that kind of lyrical flavor, about tenement living. In the song, the singer has fallen in love with a woman who lives in the apartment directly below him but has no clue as to her interest, so he asks her to respond by either knocking three times on the ceiling (yes) or banging twice on the pipe (no), and the chorus includes sound effects of the two choices. (However, the song never states her response.)
who sings knock three times on the ceiling if you want me
L. Russell Brown Irwin Levine