The "Elegant Solution"
This guide focuses on a cost-effective, code-compliant design for a 3-story, mixed-use or multi-family building in Massachusetts that avoids the high cost of an elevator.
Key Code-Hacks
This design leverages specific thresholds in the International Building Code (IBC) and Fair Housing Act (FHA) to maximize density while minimizing major costs.
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Ground Floor Accessibility: At least one ground floor unit must be accessible/adaptable. This is critical to avoid triggering an elevator requirement.
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Single Stair Egress: With a full NFPA 13R sprinkler system, a single stairway can serve up to four units per floor on the upper levels of a 3-story building.
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Travel Distance Limits: The exiting distance from the furthest point inside an upper-floor unit to the stairwell entry must not exceed 125 feet.
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Construction Type: Utilizes Type V wood frame construction, which is cost-effective for buildings of this scale.
Example Building Massing
Floor 3 (4 Residential Units)
Floor 2 (4 Residential Units)
Ground Floor
Single Stair
Interactive Proforma Dashboard
Model the financials for a hypothetical mixed-use 4-plex in Metrowest. Adjust the sliders to see how key variables impact your potential return.
Project Assumptions
Total Project Cost
$1,737,500
Net Operating Income (NOI)
$107,681
Capitalization Rate
6.20%
Financing Pathways
Compare the two primary financing routes for a four-plex project: owner-occupied FHA loans versus investor-focused conventional loans.
Owner-Occupant (FHA)
Ideal for "house-hacking." Offers lower down payments and more flexible credit requirements, but you must live in one of the units.
Loan Limits (4-Unit, High-Cost MA)
Massachusetts' high-cost areas allow for significantly larger loan amounts, making bigger projects feasible under conforming limits.
Construction Loan Bridging
New builds require a short-term construction loan that's later replaced by permanent financing. You have two main options for this process.
One-Time Close
Combines construction and permanent loans into one. Fewer closing costs and you lock your final rate upfront.
Two-Time Close
Two separate loans. More flexibility, but more closing costs and your final rate isn't locked.
Key MA Building Codes
A four-plex is not treated like a single-family home. Understanding these core requirements from the Massachusetts State Building Code is essential.
R-2 Occupancy
A 4-unit building falls under R-2 (multi-family residential), triggering stricter codes than single or two-family homes.
Fire Safety
Requires a 1-hour fire-rated separation between units and an automatic sprinkler system (typically NFPA 13R).
Egress
Requires two means of egress if occupant load or travel distance is exceeded. Egress windows are mandatory for sleeping rooms.
No Elevator (If...)
An elevator can be avoided in a 3-story building if there's an accessible ground-floor unit and it uses a single stair design.
Cost-Saving Incentives
Massachusetts offers powerful programs to lower costs and streamline development for projects that align with state housing and climate goals.
MBTA Communities Act
Mandates 177 communities to create zoning for "as of right" multi-family housing near transit. This simplifies permitting and reduces entitlement risk in designated zones, a huge benefit for developers.
Accessory Dwelling Units (ADUs)
The Affordable Homes Act allows ADUs (up to 900 sqft) "as of right" in many areas. This signals a statewide push for densification that supports multi-unit projects and can offer additional revenue streams.
Mass Save® Incentives
Provides significant financial rebates and support for building high-performance, all-electric homes. Designing for energy efficiency from the start directly lowers construction and long-term operating costs.
State & Local Grants
Programs like MassDevelopment's "Community One Stop" and local CDBG/HOME funds offer grants for projects that address housing shortages, especially in targeted redevelopment areas.
ONE Mortgage Program
Offered by MassHousing for first-time buyers, this program features low down payments and no PMI, making it a great option for an owner-occupant of a 2-3 unit property.
Down Payment Assistance
MassHousing offers up to $30,000 in down payment assistance in every city and town, significantly reducing the upfront cash needed for a purchase for eligible buyers.