Duplexes Are Back Addressing Missing Middle” Housing

By: Larry W. Garnett, FAIBD, House Review Lead Designer

(November 12, 2024) — ProBuilder is reporting a growing number of cities and towns are changing their codes to allow duplexes to be built in single-family neighborhoods. These designs offer inspiration for new possibilities. Duplexes are making a comeback for many reasons, the least of which aren’t cost-effective construction and rental income potential for homeowners.

Exterior view of a duplex home, The Turnberry, designed by Scott Gardner Architect — This three-story duplex by Scott Gardner Architect is designed for an infill location. Scroll down for more information about the project. (Images: courtesy Scott Gardner Architect)

Duplexes provide a viable, low-density housing option. Arranged side by side, front to rear, or as stacked flats, duplexes were historically built alongside single-family homes—until restrictive zoning ordinances limited their role in those neighborhoods and, as a result, their share among housing types.

More recently, a growing number of cities and towns are changing such codes to again allow duplexes to be built in single-family neighborhoods. The goal is to more prominently address the need for “Missing Middle” housing (a term coined by architect Daniel Parolek). And duplexes provide higher densities and more attainable pricing while still being compatible with adjacent single-dwelling units.

To showcase what duplexes can do, our design team created street-facing elevations that would enhance most single-family neighborhoods, while interior motor courts and rear-entry garages help solve parking challenges.

Tandem Duplex four-pack

ARCHITECT: Dawn Michele Evans, AIA, NCARB, The Evans Group, dmichele@theevansgroup.com, 407.650.8770
DIMENSIONS: Width: 33 feet Depth: 110 feet Living area: 2,303 sf

Tandem duplexes are an increasingly popular solution to escalating lot costs, and jurisdictions are becoming more accepting of this configuration within single-family infill neighborhoods.

Our developer/builder clients initially expressed concern that either the front or the back unit would sell, but not both equally. Yet, in every case where we have designed tandem duplexes, we’ve found that the units have sold equally well at the same price.

These three-bedroom homes live like single detached units because the only shared wall is between the garages, eliminating sound transfer between the homes.

Elevation of design for tandem duplex homes

The first floor is large. It features an open floor plan with the kitchen conveniently located adjacent to the garage. A full bath on the first floor allows a flex space to be used as an office/den or a bedroom.

Upstairs, all bedrooms are designed to accommodate a king-size bed, while a loft niche provides space for gaming or studying separate from the main living areas.

Three-bedroom tandem duplex homes that live like single detached units

A The wall between the garages is the only shared wall between the units

B Concealed AC compressor and trash bin storage

C Generous private outdoor living space

D Flex space on main floor for office or guest bedroom

E No living space above garages eliminates noise transfer between units

F Flexible-use loft space

Site Plan For A Series Of Four Three Bedroom Tandem Duplex Homes

The Turnberry

ARCHITECT: Scott Gardner, Scott Gardner Architect, scott@sgardnerarchitect.com, 919.320.3022

DIMENSIONS: Width: 26 feet / Depth: 52 feet / Living area: 2,303 sf

This three-story duplex is designed for a desirable infill location where land is at a premium.

Rear-loaded garages deliver optimal street frontage and allow for a porch-forward design with outdoor living spaces on all three levels to take advantage of views.

An elevator and first-floor flex space enable the owners to age in place or host an elderly family member or overnight guests.

Generous closets and an oversized garage provide ample storage—all in a tight but comfortable, light-filled footprint.

Floor Plans For Duplex Homes By Scott Gardener Architect

A Front porch enters to an office/bedroom

B Owner’s entry from the garage with direct access to the elevator

C Oversized two-car garage provides storage or hobby space

D Outdoor living on the second level

E Elevator and stairs both land at the kitchen for easy transfer of groceries

F Two walk-in closets serve the primary suite

G Outdoor living on the third level

H Flex-use bonus room with a full bath

Duplex Cluster

DESIGNER: Seth Hart, DTJ Design, shart@dtjdesign.com, 303.443.7533

DIMENSIONS: Width: 70 feet / Depth: 120 feet / Living area: 1,530 – 1,650 sf

These paired duplexes are mirrored to elegantly frame a central motor court.

Designed with privacy in mind, the rear units feature front doors accessed from shared walkways, enhancing the entry experience while minimizing street-level density.

Each unit boasts private outdoor living spaces, two bedrooms, and an oversized two-car garage that is ideal for an active adult lifestyle.

Elevation Renderings For The Duplex Cluster Design By Dtj Design

Elevation Options For The Duplex Cluster Design By Dtj Design

The layout thoughtfully positions the common wall between duplexes along the garage, secondary bedroom, and bath, ensuring optimal privacy between units.

This design fosters a sense of community while respecting individual space, offering a harmonious blend of convenience and tranquility.

A Rear-unit front doors along a shared walkway enhance both privacy and the entry experience

B Private outdoor space for each unit

C Oversized two-car garage for each unit provides extra storage or hobby space

D Common wall located between garages and secondary bedrooms maximizes privacy between units