There are several differences between attached and detached infill homes.
The most apparent difference between the two is that attached infill homes are constructed in pairs and share a common wall with one another. Detached infill homes on the other hand do not share a common wall and do not necessarily have to be constructed in pairs. 

Pairs of attached infill homes are most commonly constructed on 50-foot wide lots and are only occasionally constructed on lots that are much wider than 50 feet whereas detached infill homes are constructed on lots of all shapes and sizes. The most common infill homes that we see throughout Calgary’s inner city, both attached and detached, are constructed in pairs and on 50-foot wide lots.

One of the biggest differences between the two styles of homes involves the floor plan. A pair of attached infill homes constructed on a 50-foot wide lot will each have a floor plan width of roughly 21 feet whereas a pair of detached infill homes constructed on the same 50-foot wide lot will each have a floor plan width of roughly 17 feet. This 4-foot difference in floor plan width makes a tremendous difference when it comes to floor plan layout options.