No 81 was uninhabited at time of 1881 census. I wonder if it might have been a 'postal address', shared by various businesses.
Any more clues? What do you think J Tall invented? What suggests he lived on Blackman Street?
There was an Architect, Joseph Tall and family, living in Belvoir Road at 1891. He, or more likely his then 29yr old son, Joseph Tall, concrete builder, was possibly the same chap of "Tall's Patent Apparatus" of timescale, with some connection to its use in concrete instead of building with bricks.
A few other J Tall entries in London area at 1891, but none claiming to be an Inventor.