Duplex: Side-by-Side


A small (1 to 1.5-story), detached structure that consists of two dwelling units arranged side-by-side, each with an entry from the street. This type has the appearance of a small-to-medium single-unit house and may include a rear yard.

Typical Specifications

Lot Front-loaded Rear-Loaded
Width* 55–75 feet 40–70 feet
Depth* 100–150 feet 100–150 feet
Area* 5,000–11,250 sq. ft. 4,500–10,500 sq. ft.
  0.11–0.26 acres 0.10–0.24 acres
Number of Units 2 units 2 units
Typical Unit Size 600–2,400 sq. ft. 600–2,400 sq. ft.
Net Density 8–17 du/acre 8–19 du/acre
Gross Density 6–13 du/acre 7–14 du/acre
Parking Ratio*
On-street Spaces 2–3 2–3
Off-street Spaces 1 per unit max. 1 per unit max.
Front* 10–25 feet
Side* 5–12 feet
Rear (main building)* 30–60 feet
Between Main and Accessory Buildings 10–20 feet
Building Size
Width 28–55 feet
Depth 28–60 feet
Height (to eave)* 20–24 feet
* Varies based on context

Idealized specifications take the best characteristics of this type and update them for today’s typical building standards, serving as a model for new development.

Rear Loaded

Ideal Specifications

Width 50 feet
Depth 130 feet
Area 6,500 sq. ft.
  0.15 acres
Number of Units 2 units
Typical Unit Size 612 sq. ft.
Net Density 13.4 du/acre
Gross Density 10.3 du/acre
Parking Ratio 2 per unit
On-street Spaces 2
Off-street Spaces 2
Front 30 feet
Side 10 feet
Rear (main building)
Between Main and Accessory Buildings
Building Size 1,224 sq. ft.
Width 36 feet
Depth 34 feet
Height (to eave) 14 feet

The following example(s) show this housing type documented as real-world examples as they exist today. NOTE: Documented examples may be not be up to today’s local building code standards. See the Idealized tab for up-to-date specifications in line with modern building standards.