Prefab & Modular ADUs·Updated March 2026

Prefab ADU Builders in Sacramento

Factory-built modular ADUs delivered and installed on your Sacramento property. Faster timelines, predictable pricing, and quality-controlled construction.

$100K – $250KTypical Cost$180–$350/sqft

3 – 6 MonthsTimeline50% faster than custom

80 – 90%Factory BuiltBuilt off-site

1 – 4 WeeksOn-Site InstallMinimal disruption

What Is a Prefab ADU?

A prefab (prefabricated) or modular ADU is a housing unit that is 80–90% built in a factory, then transported to your property and installed on a prepared foundation. The remaining 10–20% of work — utility connections, foundation tie-downs, and finish details — is completed on-site.

Prefab ADUs have surged in popularity in Sacramento because they offer faster construction timelines (3–6 months vs. 8–14 months for custom builds), more predictable pricing (factory-controlled costs reduce change orders), and less disruption to your daily life during construction.

California's ADU laws treat prefab units the same as site-built ADUs — they require the same permits and must meet the same building codes. Many prefab companies handle the entire process from design through permitting and installation.

Prefab vs. Custom-Built ADU: How They Compare

Factor	Prefab / Modular	Custom Site-Built
Cost per sqft	$180 – $350	$300 – $500
Total timeline	3 – 6 months	8 – 14 months
On-site disruption	1 – 4 weeks	4 – 8 months
Design flexibility	Limited to catalog models	Fully customizable
Price predictability	High — fixed factory pricing	Medium — change orders common
Quality control	Factory-controlled environment	Depends on contractor
Financing	Some offer in-house financing	Standard construction loans
Resale value	Comparable to site-built	Comparable to prefab