# Design ideas for Standard 6-3 and Standard 8-3 multi-unit buildings The Connected Communities ordinance extends the elimination of off-street parking mandates to RM-5, RM-5.5, RM-6, and RM-6.5. (Parking mandates already could be relieved in B, C, D, and M zoning districts.) This Knowledge Base Article shows representative designs for a six to eight unit building with two or three car parking spaces. - Learn how to locate a qualifying or eligible property, and understand zoning requirements, in the [[Standard 6-3, 8-3 building|main article]] - Learn more about the [[Connected Communities]] *This Knowledge Base Article describes our best interpretation of Chicago codes and and is not legal or architectural advice.* ## Design feasibility [Aggregate Studio](https://aggregate-studio.com) is a Chicago-based architecture firm and created these graphics to study the feasibility of constructing a Standard 8-3 building. It has four stories, eight 1-bedroom units, two stairs, and two off-street car parking spaces. The massing diagram shows the required side, rear, and front setbacks, and the rear yard open space, in an RM-5 zoning district.  *Above: a massing diagram for a Standard 8-3 design showing two stairs, by [Aggregate Studio](https://aggregate-studio.com)*  *Above: A floor plan design showing two stairs. The original design with three stairs is at the end of the article.* ### Notes about this design - The building can be built as Type 3A (exterior masonry) or Type 5A (wood frame). A Type 5A construction type necessitates a sprinkler system. - [Aggregate Studio](https://aggregate-studio.com) also created a building with two stairs but a corridor would likely be required and this reduced the unit sizes and created suboptimal unit layouts. Contact Josh Mings at [Aggregate Studio](https://aggregate-studio.com) to explore the Standard 6-3 and Standard 8-3 designs further. Alternative designs could include porches, accessible units on the ground floor, penthouse units, and a roof deck. Learn more about the project from Mings's perspective on the [Aggregate Studio website](https://aggregate-studio.com/chicago-housing-8-flat/). ## Description of a "Standard 6-3" A Standard 6-3 is a six-unit building that's two, three, or four stories tall and has one to two units per floor and zero to three car parking spaces that can be built on a standard size lot in an RM-5 or higher zoning district. (It can actually be built on a lot that's smaller or larger than standard size of 3,125 s.f. but we're sticking with the standard size because of how ubiquitous they are.) ### Design considerations for Standard 6-3 After determining setbacks for a standard size lot, there will be about 72 feet of lot depth and 20 feet of lot width available for the building, resulting in a footprint of 1,440 s.f. This zoning assessment also leaves more than enough room for the 216 s.f. of rear yard open space (RYOS) that's required. Hypothetically a property owner could get relief to reduce the extend the building into the rear setback and still provide minimum RYOS. Relatedly, floor area ratio (FAR) in RM-5 is 2.0, allowing the building to have 6,250 s.f. of floor area. A three story building will only need 4,320 s.f. For a six-unit building this means an average of 720 s.f. unit sizes, enough for every unit to have a 1-bedroom layout. Alternatively, some units can have a 2-bedroom layout in ~1,000 s.f. while the other unit on the floor is a studio in ~440 s.f. (not including stairways). Consult a Chicago-based architect to calculate exiting requirements and the number of exit stairs that would be needed. ## Description of a "Standard 8-3" A Standard 8-3 is an eight-unit building that's three, four, or five stories tall and has one to two units per floor and zero to three car parking spaces that can be built on a standard size lot in an RM-5 or higher zoning district. (It can actually be built on a lot that's smaller or larger than standard size of 3,125 s.f. but we're sticking with the standard size because of how ubiquitous they are.) This Knowledge Base Article shows designs; learn how to locate a qualifying or eligible property, and understand zoning requirements, in the [[Standard 6-3, 8-3 building|main article about Standard 6-3, 8-3]]. # Original design This version has three stairs, which has slightly larger units and different unit layouts. The "Standard 6-3" design typology would benefit significantly from single stair reform.  *Above: Massing diagram for a Standard 8-3 design showing three stairs, by [Aggregate Studio](https://aggregate-studio.com)*  *Above: A possible unit layout for the Standard 8-3 design showing three stairs. The three stair option allows slightly larger unit layouts because less space is dedicated to a corridor. By [Aggregate Studio](https://aggregate-studio.com)*