I have heard/seen people say/write "She is 5 feet 10 inches tall" and "She is 5-foot-10." But in formal writing, is there a convention? I found both "8-foot-tall" and "nine-feet tall" in online sources.
The bronze, 8-foot-tall LBJ sculpture is slated to be installed at downtown's Little Tranquility Park, bound by Capitol, Walker, Bagby and Smith streets. (source)
Nine-feet tall and bronze, the monument to the famous novelist has been erected in the grassy center of the 13.7-acre park's circular drive. (source)