Modular Homes vs. Prefabricated Homes: Which Is Better for ADUs?
When planning an ADU, homeowners often come across two similar construction types: modular homes and prefabricated homes. While both are built off-site to save time and reduce costs, the way they’re designed, transported, and assembled makes them very different. At MF ADU, we help you understand these differences so you can make the best decision for your home and budget.
What Is a Prefabricated ADU?
Prefabricated (or “prefab”) ADUs are built in parts—such as wall panels, roof sections, and floor systems—in a factory. These components are then transported to your property and assembled on the foundation.
Why homeowners prefer prefab ADUs:
✅ Faster construction and installation
✅ Lower costs due to efficient factory production
✅ Highly customizable layouts and finishes
✅ Great for small lots and urban properties
What Is a Modular Home?
Modular homes are also built in a factory, but instead of panels, they’re built in large fully completed sections or “modules.” These modules already include walls, flooring, wiring, plumbing, and fixtures.
Modular homes are known for:
✅ Strong structural durability
✅ Built to the same building codes as full-size homes
✅ Ideal for larger multi-bedroom homes or multi-story buildings
But they also come with challenges:
❌ More expensive transportation and crane installation
❌ Less flexibility for small ADUs
❌ Harder to modify once built
Which Option Is Better for ADUs?
For most homeowners building an ADU, prefabricated construction is the better option. Here’s why:
Faster approval and construction process
More budget-friendly than modular builds
Easier to install in tight backyard spaces
More flexible for rental units, guest suites, or family housing
Modular construction is a great solution, but it’s more practical for full-size homes or large multi-module projects, not smaller ADUs.
Did you know?
Did you know? Prefabricated ADUs can be built and installed up to 50% faster than modular homes because factory production and site preparation happen at the same time.
Building Smart with MF ADU
Choosing the right construction method can save you time, stress, and money. At MF ADU, we specialize in prefabricated ADUs that are fast to install, fully customizable, and built to California’s strict standards.
Explore our prefabricated ADU models and see how we make the process simple from start to finish.
Frequently Asked Questions
Are modular and prefab homes the same?
Not exactly. All modular homes are prefabricated, but prefab ADUs are usually built in smaller components instead of full modules.
Which one is cheaper for ADUs?
Prefabricated ADUs typically cost less due to faster assembly and lower transportation costs.
Can I customize a prefab ADU?
Yes. You can choose layouts, finishes, accessibility features, and design styles.
Do they follow California building codes?
Yes. Both must meet state and local building code requirements.
Which one is easier to build in a small backyard?
Prefabricated ADUs are easier to transport, position, and assemble on narrow or limited-access lots.