[mjmahone17]

Double loaded corridors fundamentally change the composition of buildings. If you look at example floorplans, single staircase buildings typically feature 2-3 bedroom apartments, because giving every bedroom a window is easier, while double loaded corridors end up mostly with deep studios and 1-beds.

Building new housing in the US is not cheap, and reducing the leasable or buyable square footage by 10% can move projects from being profitable to build to not. Especially when the quality of the remaining square footage goes down (as it does when you have 30’ deep units with only one wall with windows).

[Retric]

There’s a multitude of options here for various floor plans. One of the classic solutions is an external fire escape which is cheap per apartment and isn’t impacting floor space. People may dislike the aesthetics though.

Construction costs scale to the market segment you’re targeting. It’s common to aim up market with new housing but the cost of marble isn’t the same as the cost of housing. So be careful you’re looking at the minimums not what it takes to attract high end buyers.