Well done with the maps Mike, Karen will be pleased.
Karen,
Irving St. - I was born in 1949 at 1, Court 12, just to the west of Sutton St. - but it was numbered 1 back of 66 or 1/66 in my day, as your great-grandfather's house would have been numbered something like 2/141. Irving St. was numbered on the north side, west to east down to Bristol St. and then back up the south side east to west. When you look at old photos on this forum they usually follow that numbering - as they do on this website page
http://www.oldladywood.co.uk/irvingstreet.htm. There are also words on, and photos of, the style of living in such back-to-back housing in Ted Rudge/Mac Joseph's book "Birmingham, We Lived Back to Back" - bit of my life gets a mention on p95. You can still experience living in Irving St. by staying at the Ibis Hotel, just up the hill (west) from your great-grandfather's house - the street's changed quite a bit! You could of course also visit the National Trust Back to Back houses in Hurst Street. That area of the town is where my maternal agricultural labouring ancestors, by the name of Bodfish, from Oxfordshire, first came to live and work in the town. It was called the Ladywell area in those days - the ancient Lady Well is marked on Mike's map - in what became a timber yard, where some of my ancestors worked. I'm paying Cornwall a flying visit in a couple of weeks - perhaps you ought to visit Birmingham to tread your newly found ancestor territory!
Bill