Fourplex & Quadplex Plans (2–4 Units)

Two-to-four-unit buildings are the most financeable way into rental real estate: a fourplex still qualifies for residential financing and house-hacking, while producing four rent checks. We design duplex, triplex and fourplex buildings that squeeze the most rentable bedrooms out of every square foot and pass residential code.

In 2026 small-multifamily construction runs roughly $150–$250 per square foot, or about $140,000–$300,000 per unit depending on size, finish and region. A clean plan set with per-unit dimensions and separate metering is what lenders and permit offices want to see.

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2–4 units, residential codeMaximize rentable bedroomsCAD/DWG + cost estimate

Small multifamilyDuplex · triplex · fourplex

What's included

Building plan for 2, 3 or 4 units — stacked or side-by-side
Per-unit floor plans and elevations, fully dimensioned
Rated party-wall and floor/ceiling fire separation
Separate metering, parking and entry planning
MEP layouts and editable CAD/DWG files
RSMeans-based construction cost estimate
Permit planning documentation

Built for financing and house-hacking

A 2–4 unit building is treated as residential for financing, which is why it is the classic house-hack: live in one unit, rent the rest. We lay out the units so the owner unit lives well while the rentals stay efficient and appealing.

Fourplex build cost per unit (2026)

Configuration	Typical cost / unit	Notes
Duplex (2 units)	$160k – $300k	Side-by-side or up/down
Triplex / Fourplex unit	$140k – $260k	Efficiency improves per unit
Plus site work	+$40k – $120k	Parking, utilities, stormwater

Excludes land. Your number depends on unit mix, region and finish — get an RSMeans-based estimate below.

Get an exact number for your project

A designer prepares your full package with an RSMeans-based cost estimate — start the short brief.

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Frequently asked questions

Why build a fourplex instead of a single rental?+

A 2–4 unit building still qualifies for residential financing but produces multiple rent checks, and you can live in one unit while the others cover the mortgage — the classic house-hack. It is the most accessible on-ramp to multifamily.

Stacked or side-by-side units?+

Both work; it depends on your lot and market. Side-by-side (townhome-style) rents like houses; stacked flats fit more units on a tight lot. We design to your site and goals.

Do you plan separate metering?+

Yes — separate electric, and often water, per unit is standard for rentals, and we plan the service and mechanical space for it.

How many units can you plan?+

Duplex through fourplex here; for 5+ units and apartment buildings, see our multifamily development plans.

Plan your fourplex

Tell us your unit count and lot — a designer prepares your small-multifamily plan and cost estimate, and contacts you within 1 business day.