Prefab vs. site-built · Los Angeles
Prefab ADUs in LA —
or something better?
Prefab promises speed and a fixed price. But on most LA lots, a custom site-built ADU ends up costing about the same — and gives you more control, better lot-fit, and stronger resale. Here's the honest comparison.
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600+
ADUs delivered
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39
Plans to start from
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100%
Customizable
First, the fair part
Why prefab sounds great.
We get the appeal — and we won't pretend it isn't real. If you're researching prefab ADUs, here's what's genuinely attractive about it.
Speed
Factory built.
Units are assembled indoors while you wait — no weather delays on the build itself.
Simplicity
Pick a model.
Choose from a catalog, see a price, and you're done deciding. Less to think about up front.
Predictability
Fixed sticker price.
The advertised price feels reassuring — a known number before you commit.
The honest comparison
Prefab vs. site-built, factor by factor.
No spin. Here's how the two approaches actually stack up for a Los Angeles homeowner — including the costs prefab brochures leave out.
All-in cost
Sticker price looks low, but add delivery, crane, foundation, utility hookups, site prep & finishing — the real total often lands near site-built.
✓ One transparent number that already includes foundation, utilities, and finish work. No surprise add-ons after the box arrives.
Timeline
Factory build is fast on paper, but permitting, site work, delivery scheduling & crane day stretch the real timeline — and a factory delay stalls everything.
Permitting and site work happen in parallel. Predictable LA schedule managed by one local team.
Customization
You pick from a fixed catalog of models and sizes. Real changes are expensive or simply not offered.
✓ Design it around your lot, your style, and your budget — layout, finishes, rooflines, indoor-outdoor flow.
Your lot
Narrow LA lots, hillsides, tight side-yards and no crane access can make delivery impossible — or wildly expensive.
✓ Built in place. Works on the tight, sloped, hard-access lots that are normal across LA.
Quality & durability
Built to ship down a freeway, which constrains materials and connections. Quality varies a lot by manufacturer.
✓ Standard residential construction — same materials and methods as a custom home, inspected on site.
Financing & appraisal
Some lenders and appraisers treat modular units cautiously, which can complicate HELOCs and refis.
✓ Appraises and finances like any home addition. Cleaner path for HELOCs and construction loans.
Resale value
Resale is improving but still less predictable than conventional construction.
✓ A permitted, site-built ADU adds documented square footage that buyers and appraisers understand.
Want the real numbers for your lot? Try the ADU cost calculator →
The part nobody mentions
Where prefab struggles in LA.
A prefab unit is a finished box that has to be trucked in and craned over your house. On the lots that are normal across Los Angeles, that's exactly where it falls apart — and where the "fixed price" starts climbing.
Common LA dealbreakers
- ✕Narrow lots & tight side-yards a module can't pass through
- ✕Hillside & sloped lots with no level set-down
- ✕No street/crane access or overhead power lines
- ✕Limited sizes & layouts — no true customization
- ✕Surprise site, foundation & utility costs after the quote
The better-built option
Custom speed, custom-home result.
We've delivered 600+ ADUs across Greater Los Angeles. You get the convenience prefab promises — start from a proven plan, one team, one timeline — without the catalog limits.
Start from 39 proven plans
Skip the blank page. Pick a plan that fits your lot and customize from there.
Browse floor plans →Designed around your lot
Narrow, sloped, tight access — we build in place, so your property's quirks aren't dealbreakers.
In-house design + permitting
We handle LADBS and local permitting end-to-end. Local expertise, no handoffs.
Transparent all-in pricing
One number that includes foundation, utilities, and finishes — no post-delivery surprises.
Estimate your cost →Licensed & bonded builders
Vetted, licensed, bonded partner contractors — and we stay your single point of contact.
Built to appraise & resell
Conventional construction that finances cleanly and adds documented square footage.
Real, site-built
ADUs we've built across LA.
Questions
Prefab ADU questions, answered honestly.
Still have a question? Ask us during your free consultation.
Is a prefab ADU actually cheaper than building one?
Usually not, once you add everything in. The factory price you see rarely includes delivery, the crane, the foundation, utility connections, permits, site prep, and final finishing. By the time the unit is livable on your lot, the all-in cost is often within a few percent of a site-built ADU — except now you also accepted a fixed design. We'll give you a transparent, all-in number so you can compare honestly.
Is prefab faster?
The factory build is fast, but it's only one part of the timeline. You still need permits, site work, a foundation, and a delivery + crane day — and if the factory runs behind, your whole project waits. We run permitting and site prep in parallel with a local crew, which keeps a site-built ADU's real-world timeline competitive and far more predictable.
Can a prefab unit even fit on my Los Angeles lot?
Often that's the dealbreaker. A finished module has to be trucked in and craned over your house into the backyard. Narrow lots, hillside properties, tight side-yards, overhead power lines, and no street access for a crane make delivery impossible or very expensive on many LA properties. A site-built ADU sidesteps all of it because we build it where it stands.
Do you sell prefab ADUs?
No — and that's on purpose. We build custom, site-built ADUs because they give Los Angeles homeowners more control, better lot-fit, cleaner financing, and stronger resale than a catalog box. If you came in wanting prefab, book a free consultation and we'll show you side-by-side what a custom build costs and looks like for your exact lot. No pressure.
What's the catch with prefab?
The appeal is real — speed and a fixed price are great. The catches are: limited designs, surprise site costs, delivery constraints on LA lots, and financing/resale friction. For some big, flat, easy-access lots prefab can pencil out. For most LA properties, a site-built ADU ends up costing about the same and serving you better.
How much does a custom ADU cost in Los Angeles?
It depends on size, type, and finish level — most detached ADUs land in a wide range depending on scope. Use our ADU cost calculator for a quick estimate, or book a consultation for a real all-in number for your lot.
Free ADU consultation
Compare prefab vs. custom for your lot.
Tell us about your property and we'll show you a real, all-in number for a custom site-built ADU — side by side with prefab. No pressure, just honest answers.
