I think it is important and valuable to build Accessible/Adaptable apartments as  currently required under HUD's Fair Housing Design Manual .  Here's how to do that in a straightforward three story walk-up building you could build with ordinary residential construction trades in your local market:

The requirement for apartment building or mixed use buildings containing four or more units, and built without an elevator is that all of the ground floor units must be Accessible/Adaptable.  If the 1st floor has no residential units on it, (say because the ground floor is occupied by commercial space or parking garages), then the next floor (the 2nd floor) becomes the "Ground Floor" for the purposes of compliance with the federal Fair Housing Act and you would have to install an elevator for access to that floor unless the building was adjacent to a steep enough grade to provide access to the 2nd floor without an elevator or lift.  As I explained in an earlier post that seems to be getting a fair amount of play, The International Building Code (IBC) allows you to build a three story TYPE V (wood frame) structure with fire sprinklers with a single exit stair, as long as the upper floors do not have more than 4 units on each of them and that the travel distance from the farthest location within each unit is less than 125 feet from the exit stair enclosure.  Follow the link for the specific IBC code citations:

Another Look at how to build a 3 story building without an elevator

The photos above show some capably designed 3 story buildings.  It is possible to do this.  If you have doubts and you need some help,  I suggest that you contact the good folks at Union Studio in Providence, RI They designed the two 6-plex buildings on the lower left or Eric Brown at Brown Design Studio in Savannah Eric designed the white 6-plex walk-up in the larger image on the right.  My able partner David T. Kim designed the 22 unit Hutchinson Green Apartments in the upper left as our first major project after the Great Recession.

So 3 Story Urbanism is no problem?  Okay, admittedly that title does cross the line into Click Bait, because while these hard working modest buildings are very useful in creating 3 story urbanism, your local zoning code with it's needlessly deep building setbacks, or bloated off-street parking requirements may make it quite difficult to build good #3StoryUrbanism.  But as you can see, but the International Building Code should not be an issue for you.

Bloated parking requirements will mess up your site plan so that you cannot build the same way as the venerable 1920's 3 story apartment building across the street.  Municipalities are famously bad at guessing how much parking you should be required to build on your private parcel.  Many cites will not even give you credit for the parking spaces at the curb in front of your potential building -as if they do not physically exist.  Unnecessary parking takes up space, creates additional impervious surface that you have to address for the storm water requirements, and those additional spaces cost money to build and maintain.  Bloated parking screws up perfectly good projects every day.  The development math for parking you don't need never works in your favor.

single-story-commercial-bay

110525_4x-single-story

I think there are lots of great precedents for small single story main street buildings that work well.  Above are some studies David Kim and Will Dowdy did on small, shallow storefront spaces that could be used as parking lot liners or in conjunction  with small apartment buildings and cottage courts located behind the small commercial/flex building to provide mixed use without requiring the use of commercial steel pipe fire sprinklers that can be required if the residential and non-residential Occupancy Types were combined into in one mixed use building.

The intent was provide a wide/shallow space that could be flexible.  We settled on a depth of 26' as this leaves an 18' dimension between the 8 x 8 accessible restroom and the storefront.  We were also looking to keep any columns or other intermediate structure out of the floor plan and 20'-32' of depth is readily spanned without going nuts on the truss design.  You can get pre-engineered bar joists at 40' long, but we wanted to keep the construction technique within the skills of residential trades.

Keeping the depth modest allows for daylighting of the space from a transom and light shelf over the storefront and awning.  Spaces this small are easily heated and cooled with a ductless mini-split heat pump/air conditioner.

Using a single pitch roof truss, sloping from the street side to the rear, with a parapet on the street side can provide lots of room for signage, while screening compressors or kitchen hood fans from the street view. 

Buildings that are flexible enough to house small and inexpensive workspace for retail, services, food and drink, etc. should be in the Small Developer's tool box.  You may know an under-utilized parking lot that could be lined with something like this.  Could be good way to follow up on testing the location with some food carts.

Steve Mouzon has some very interesting thoughts along these lines.  His blog has better production values than mine does, so I encourage you to click through and check it out.  

Steve Mouzon's Blog Original Green

I was on a video call with my able partner David Kim this morning.  When the conversation turned to the elaborate requirements of the California Energy Code, he had what I thought was a really great idea. "What if we could build without air conditioning?"

I think that's genius.  There are lots and lots of Architects and Sustainable Design people running around these days.  If we can challenge that brain trust to design buildings that do not require air conditioning, I'm sure they could come up with all kinds of great stuff.