Backyard ADU Kit: What’s Actually in the Box, What It Really Costs, and Who It’s Right For (2026)

The short answer

A backyard ADU kit is a panelized, pre-cut, or modular package — walls, roof, and often windows and doors — that ships flat-packed or in modules and gets assembled on a foundation you build separately. In 2026, real verified kit and base-package prices range from $9,250 (a 300 sq ft steel-frame studio shell on Home Depot) to $116,000 (an 800 sq ft Modular Home Direct steel-frame base package), with most homeowners landing between $25,000 and $75,000 for the kit itself.

Here’s the part most listings bury: the kit price is usually 20% to 35% of your finished, permitted, move-in-ready cost. A $50,000 kit typically becomes a $130,000 to $200,000 total project once you add the foundation, utilities, interior finishes, permits, labor, and impact fees. The single line to internalize before you do anything else: “Kit” describes how a structure is sold. “ADU” describes whether your city will let you live in it. Those are two different approvals.

This page exists to end that confusion. We’ve pulled seven real 2026 kits with sources, built the kit-to-finished math, decoded the permit reality across seven major cities, and laid out who a kit is actually right for — and who should walk away from the category entirely.

Backyard ADU kit: price vs. finished-cost reality, at a glance

Prices verified from public retailer and manufacturer listings on May 28, 2026. Finished all-in costs run 2×–5× the kit price — see the hidden math.

What is a backyard ADU kit, exactly?

A backyard accessory dwelling unit (ADU) kit is a manufactured package of pre-engineered building components — typically wall panels, roof panels or trusses, doors, windows, and structural hardware — shipped to your property for on-site assembly on a foundation you build separately. It is not, by itself, a finished home and it is not automatically a legal dwelling. “Kit” is a product format; “ADU” is a legal use approved by your local building department under your city’s zoning and building codes.

That distinction matters because every other question on this page flows from it. The kit seller can ship you a beautiful panelized package. Your city decides whether the resulting structure can be occupied as a dwelling. Confusing those two roles is the most expensive mistake in the entire category.

A working definition

For the purpose of this guide, a backyard ADU kit is any product that meets all three of these criteria:

1. Sold as a defined package — you pay one price for a stated bundle of materials or modules.
2. Designed for on-site assembly — it’s not delivered finished and craned into place as a single unit.
3. Marketed for use as an accessory dwelling unit, guest house, in-law suite, or backyard cottage — meaning it’s intended for human habitation, not just storage.

That framing rules out two adjacent categories most homeowners initially conflate with kits: turnkey factory-finished prefabs (which arrive as completed, plumbed, wired homes craned onto a foundation — covered in our prefab ADU cost guide) and HUD-code manufactured homes (regulated federally under 24 CFR Part 3280 and treated differently by lenders and cities).

The terms sellers use — and what they actually mean

The “ADU kit” search query pulls back six different product types using overlapping language. Knowing which is which prevents most early-stage mistakes.

The 2024 International Residential Code includes Appendix BC, Accessory Dwelling Units, which gives jurisdictions a residential-code framework specifically for ADUs. Whether your city has adopted that appendix matters: it shapes minimum room sizes, ceiling heights, egress requirements, and whether certain compact designs are legally habitable in your jurisdiction.

The six categories of kit (so you stop comparing apples to bowling balls)

Backyard ADU kits sort cleanly into six predictable categories. Pick the wrong one for your situation, and you can spend more, not less, than a turnkey alternative. These aren’t brand buckets — they’re construction-method and finish-level buckets, and every kit on the market fits into one of them.

1. Bare structural shell ($9K–$30K)

Steel-frame or stick-frame skeletons with hardware and a basic envelope. Bedrock Building Group’s steel-frame kits on Home Depot are the cleanest examples: a 300 sq ft 1-bath studio listed at $9,250 (model BBG-240102) and an 863 sq ft 2-bed 1-bath at $28,580 (model BBG-242206). Best for: experienced owner-builders who plan to subcontract everything except the structure and want maximum cost control over finishes.

2. Insulated panelized shell ($30K–$75K)

Pre-engineered wall and roof panels with the envelope sealed (windows often pre-installed). Studio Shed’s DIY Summit series at Home Depot defines this category — 476 sq ft at $52,691 (Summit 476A) and 800 sq ft at $73,502 (Summit 800A). Best for: homeowners who want a weather-tight shell up fast but accept that interiors and MEP are still their responsibility.

3. SIP-based kit ($25K–$70K base)

Structural insulated panel kits where the panels themselves provide framing, sheathing, and insulation in one assembly. Mighty Small Homes’ Modern line shows the SIP pricing structure: a 256 sq ft base at $26,885, a 600 sq ft at $48,144, and a 1,200+ sq ft at $65,345. SIPs cut framing labor and improve energy performance — meaningful in jurisdictions with strict energy codes such as California’s Title 24. Best for: cold-climate or energy-strict states.

4. Full-package “near-turnkey” kit ($75K–$200K+)

A kit-format product that includes finishes, fixtures, and sometimes appliances. Studio Shed’s finished Summit series — sold by Studio Shed itself — is the canonical example: the finished Summit 800 carries a model starting price of $155,426, and the finished Summit 1000 starts at $191,523. This is the same Summit 800 model as their $73,502 DIY shell, fully finished by their own crew. Best for: buyers who like the kit ecosystem but don’t want to manage trades.

5. Tiny-home kit adapted as an ADU (variable)

Compact consumer kits sold through retail channels, often built to standards better suited to office or guest-room use than full-time habitation. Some can be permitted as ADUs if they’re built to IRC (not HUD) standards and the model has been approved in your city — many cannot. The PLuS1 “Chill Out” kit on Home Depot — a 305 sq ft 1-bed 1-bath steel-frame package listed at $22,999 — sits in this category.

6. Foldable / unitized “kit-like” products

Compact factory-finished units that fold or stack and arrive nearly complete. BOXABL’s Casita is the best-known: 19′ × 19′ / 361 sq ft, ships folded on a trailer, and is marketed for ADU and backyard use (boxabl.com). Technically not a “kit” in the panelized sense, but the buying mode is similar enough that homeowners encounter it in the same search.

How much does a backyard ADU kit cost in 2026?

Backyard ADU kit prices range from about $9,250 for a bare 300 sq ft steel shell to $116,000 for an 800 sq ft modular base package, with most homeowners paying $25,000 to $75,000 for the kit itself. These are kit-only prices, not finished-project costs — the finished, permitted cost typically runs 2× to 5× the kit sticker. We pulled seven representative kits from public retailer and manufacturer pages on May 28, 2026.

Table 1 — Seven verified 2026 backyard ADU kit prices

Prices verified directly from publicly listed retailer and manufacturer pages on May 28, 2026. Local store pricing, shipping, and current promotional discounts may vary. Always confirm the current price with the seller before ordering.

What this table is telling you

Three useful patterns jump out once you stop trying to rank these head-to-head:

Pattern 1: A 12× price spread on widely varying scope. The 300 sq ft Bedrock studio ($9,250) and the 305 sq ft PLuS1 Chill Out ($22,999) are 2.5× apart on sticker despite serving the same “small backyard structure” use case. The difference is panel pre-assembly, included hardware, and design specification.

Pattern 2: SIP kits sit between bare shells and finished panelized. Mighty Small Homes’ Modern 256 at $26,885 prices similarly to bare steel shells but delivers integrated insulation and a custom floor plan — meaningful for energy-code-strict states.

Pattern 3: At 800 sq ft, the kit category itself splits. Studio Shed’s DIY shell at $73,502 and Modular Home Direct’s complete materials package at $116,000 are technically both “kits” but represent fundamentally different products. One is a panelized shell you finish out; the other is a modular package that arrives closer to occupiable.

The hidden math: why a $50K kit becomes a $150K project

Here’s our damaging admission, said plainly: a backyard ADU kit can be the cheapest-looking option on paper and still be the easiest way to underestimate your total project. Across nearly every manufacturer we surveyed, finished all-in cost runs 2× to 5× the kit’s sticker price.

DC Structures publishes the rule directly: their California ADU page states homeowners “can generally expect their total build cost to be three to five times the price of their design and materials package, depending on site conditions and finish choices.” The clearest single illustration sits inside Studio Shed’s own pricing. Their Summit 800 sold as a DIY shell at Home Depot is $73,502. The same Summit 800 model sold finished by Studio Shed’s own ProAssembly team carries a model starting price of $155,426 — a gap of roughly $81,924. Same building. Same factory. Same panels. The difference is the foundation, the interior, the MEP rough-in, the finishes, and the labor — exactly the line items the kit-shell price excludes.

Table 2 — Kit price vs. realistic all-in finished cost

All-in ranges are illustrative national averages drawn from manufacturer-published guidance and national cost data from HomeGuide and Neighbor.com — not verified quotes for these specific projects. Actual costs depend on your state, lot conditions, finish level, and labor market. These are illustrative examples, not guarantees. Actual results depend on local market conditions, construction costs, financing terms, and regulatory approvals.

Where the gap goes

Read this as a budget builder, not as a reason to quit. The $50,000–$120,000 that lands between the kit and the keys breaks down into roughly seven categories:

• Foundation and site work: $8,000–$40,000 depending on soil, slope, and access.
• Utility connections: $5,000–$30,000+. Sewer or septic, water, electrical service from the main panel or street. Long utility runs and main-panel upgrades are the number-one budget surprise homeowners report.
• MEP rough-in and finish: $20,000–$60,000. Mechanical (HVAC), electrical wiring and fixtures, plumbing rough-in and fixtures.
• Interior finishes: $15,000–$50,000. Drywall, paint, flooring, doors, trim, kitchen, bathroom fixtures, lighting.
• Permits and fees: $1,500–$30,000 depending on city and unit size. California exempts many smaller ADUs from impact fees, so the number depends heavily on your unit size and local schedule.
• Labor and general contracting: Often 40%–50% of total finished cost if you’re not doing the work yourself.
• Shipping, crane, staging, sales tax: $2,000–$15,000 depending on distance from the manufacturer and lot access.

What the kit price usually excludes

DC Structures publishes their exclusion list openly, and it’s representative of the category. Their “What’s Included” page states that standard kits do not include installation or general contracting, construction labor, foundation labor, excavation or site work, final roofing, gutters, plumbing, electrical, HVAC, interior finishes, insulation, shipping, masonry, and several other items.

Treat the table below as your canonical kit-quote audit checklist. If a kit quote you’re considering doesn’t address every line, that’s not a kit — that’s a starting point.

Table 3 — The 13 line items a kit price usually doesn’t cover

A note on fees: California law limits or exempts impact fees for many smaller ADUs — including the common under-750-square-foot threshold — so a blanket “fees add tens of thousands” warning can mislead. Check the schedule for your exact unit size before you finalize a number.

Can your city actually permit it?

Yes — but only if the kit’s plans, foundation, and utilities match your city’s code requirements, and only if the underlying structure type is something your local building department recognizes as a dwelling. A backyard ADU kit must meet the same local zoning, setbacks, height limits, life-safety, and inspection requirements as any site-built ADU. Your city does not give a kit a special path; it gives the resulting structure a path.

That’s why we keep saying: “kit” is a product format, “ADU” is a legal status, and the gap between them is closed by your local building department.

The 2024 International Residential Code now includes Appendix BC for accessory dwelling units, giving jurisdictions a residential-code framework specifically for ADUs. Whether your city has adopted Appendix BC — and whether your kit’s design matches its requirements — is one of the first questions to verify.

Table 4 — How seven U.S. cities treat backyard ADU kits

The same kit can be permitted easily in one city and rejected in another. Below is a snapshot of how seven jurisdictions handle the backyard ADU pathway, with primary sources.

For full state-by-state and city-by-city rules, see our ADU regulations hub.

The six questions to ask your building department before you order a kit

We’ve watched homeowners spend deposits before making any of these calls. Don’t.

1. Is a detached ADU allowed at this address under current zoning?
2. What’s the maximum ADU size for this lot, this zone, and this primary-residence footprint?
3. Does the city accept panelized, SIP, modular, or container construction methods as ADUs?
4. What plan documentation and engineering stamps will the city require?
5. Does the ADU need a permanent foundation, and what foundation type does the soil report support?
6. Are there utility, fire, access, energy, or owner-occupancy rules that affect this lot specifically?

In California, statewide ADU law has overridden many of these questions in homeowner-favorable directions. Assembly Bill 68 (2019) strengthened statewide ministerial ADU approval. AB 2221 (2022) added denial-comment requirements and tightened related permit limits. AB 2533 (2024) created a path to legalize many unpermitted ADUs built before 2020. Our California ADU laws guide decodes the current rules.

Can this kit become a legal ADU at my address? (The 60-second quick test)

A backyard ADU kit can become a legal ADU only if it clears every item below. If you can’t answer “yes” or “verified” to all seven, you have a research task before you have a deposit decision.

1. Structure type — Is the kit built to the International Residential Code (IRC), not RV or HUD manufactured-home standards?
2. Code path — Has the seller confirmed in writing which building code the design meets, and will they provide stamped plans?
3. Permanent foundation — Will it sit on a permanent, engineered foundation your city accepts (not wheels, not blocks)?
4. Complete dwelling — Does it have permanent provisions for living, sleeping, eating, cooking, and sanitation?
5. Utility path — Is there a workable plan for water, sewer or septic, and electrical service to the unit?
6. Local size limit — Does the unit fit your city’s ADU size cap for your lot and zone?
7. Final approval — Is there a clear path to inspections and a certificate of occupancy or local equivalent?

Clear all seven and a kit is a real path. Miss one and that’s your next phone call — to your building department, not your kit seller.

ADU kit vs. turnkey prefab vs. site-built: when each one wins

There is no universal “best” — only a best-fit for your lot, your timeline, and how much project-coordination chaos you’re willing to absorb. Three distinct decision points consistently sort homeowners toward one of the three paths.

Table 5 — Kit vs. turnkey prefab vs. site-built, side by side

For the deep dive on turnkey prefab pricing, see our prefab ADU cost guide. For all-ADU-type cost comparisons, see how much an ADU costs in 2026.

Lot-fit decision: when a kit works and when it doesn’t

Lot conditions decide whether a kit path stays cheaper than a turnkey prefab or quietly becomes more expensive. The biggest single factor isn’t the kit — it’s whether your property’s access, slope, and utility distance let the kit deliver its intended advantages. This is where the kit format genuinely shines: panelized kits ship as flat components a small crew can carry by hand, which is exactly why they win on tight urban lots where a crane-set modular unit physically cannot reach the backyard.

Table 6 — Lot conditions and the path they favor

The side-yard access test

Before you order a kit, walk your property with a tape measure and answer five questions:

1. How wide is the narrowest access point between your driveway and the proposed kit location?
2. Can wall panels (typically 4 ft × 8 ft up to larger panelized sections) be carried by hand or do they need a forklift?
3. Is overhead clearance free of power lines, tree limbs, or eaves?
4. Where will you stage panels and materials between delivery and installation?
5. Is there enough room for a small concrete pumper or rebar delivery truck during the foundation phase?

If your narrowest access is under 8 feet, a panelized or SIP kit is almost certainly the right product format. If your narrowest access is over 12 feet and your lot is flat, you have all three options open and should pick on cost and speed.

Can you really build it yourself? The honest skill gate

Here’s our second damaging admission: most homeowners who think they’ll DIY an ADU kit will not actually DIY an ADU kit. That’s not a problem with the kits — it’s a problem with what the word “DIY” implies. Most kit marketing assumes you have framing-equivalent carpentry skills, two to three helpers, and a willingness to subcontract foundation, electrical, plumbing, and HVAC to licensed trades. Studio Shed’s own guidance says basic tools and moderate DIY skill are enough for the shell but recommends professional help for electrical, plumbing, and finish work.

Realistic shell assembly time for a first-time homeowner crew is closer to 5–14 days, not one. If you have never framed a wall, set a header, or hung a window, your first ADU is not where you want to start your construction career. That said, plenty of handy homeowners successfully assemble shells and subcontract the rest — and that’s exactly how the kit math beats turnkey.

The four skill thresholds

The trades you usually can’t DIY

Even on owner-builder projects, electrical, gas plumbing, and HVAC work are frequently restricted by state licensing rules, local permit rules, utility requirements, or inspection requirements. Refrigerant handling for HVAC, for example, requires EPA Section 608 certification regardless of who owns the home. Verify with your local building department before assuming “DIY kit” means “DIY trades.”

If a kit isn’t the right tool, that’s worth knowing now

The next step is to look at a finished prefab or modular package (see our prefab ADU cost guide) or get matched with a builder who handles the full project.

For homeowners in California’s Central Coast region, Framework First delivers California ADUs within approximately 150 miles of Monterey County. For Utah and Southern California, Nest Tiny Homes serves its approved service areas (confirm county availability). For Greater San Diego County, SnapADU builds turnkey detached ADUs. For broad national modular and prefab pathways, Modular Home Direct serves all 50 states.

Financing a backyard ADU kit

Most mainstream mortgage products weren’t designed for “buy a kit, hire trades, finish over six months” cash-flow patterns. Financing depends less on the word “kit” and more on whether the project produces a permitted improvement to real property, how funds are disbursed, and whether the lender accepts the structure type and construction method.

Fannie Mae’s Selling Guide section B2-3-02 classifies modular, prefabricated, panelized, and sectional housing as site-built when requirements are met — distinct from manufactured (HUD-code) housing. Separately, Fannie Mae’s ADU guidance under B2-3-04 confirms that standard Selling Guide loan products can be used for homes with an ADU, to renovate an ADU, or to add a new ADU. Whether your lender accepts your kit’s construction method is a different question — and it’s the one that catches buyers off guard at closing.

The four financing paths kit buyers actually use

Sorted by frequency, not by who pays the highest commission. We do not rank lenders by payout.

Path 1: Home equity loan or HELOC. A second loan secured by your existing home’s equity. Best for homeowners with substantial equity who want to fund the project from existing home value. The lender doesn’t have to underwrite the future ADU.

Path 2: Renovation or construction loan. Disburses against milestones (foundation, framing, MEP rough-in, finish, certificate of occupancy). Requires stamped plans, a fixed-bid contract, and a draw schedule. Closer scrutiny on the kit’s construction method.

Path 3: Cash-out refinance. Refinance your primary mortgage at a higher principal, taking the difference in cash to fund the build. Best when current rates are favorable and you have substantial equity.

Path 4: Cash plus phased build. Some buyers fund the kit and foundation in cash, then take out a smaller construction loan or HELOC for the finish work. Reduces lender complexity at the cost of larger upfront equity outlay.

Why HUD-code vs. IRC-code matters at the lender’s desk

This is the single most important distinction in ADU kit financing. HUD-code housing is built to federal manufactured-housing standards under 24 CFR Part 3280. IRC-code housing — including most panelized and SIP backyard ADU kits — is built to the International Residential Code as adopted by your state and city. IRC-built ADUs on permanent foundations typically qualify for conventional mortgage financing. HUD-code ADUs can qualify too, but only when they meet Fannie Mae’s manufactured-housing and ADU requirements — including real-property classification — and they are not the same underwriting path.

If your kit’s documentation can’t tell you which code path it’s built to, that’s a deposit-blocker. Ask before you order.

Who a backyard ADU kit is right for

A backyard ADU kit is the right call when you have visible construction skills (or trusted local builders willing to assemble), a flat accessible lot, a flexible 4–8 month timeline, a budget under $200K all-in, and a city that already approves kits or pre-approves similar plans. It’s the wrong call if you need a hard move-in date under six months, your lot has slope or access issues, you’ve never managed a construction project, your city requires a licensed contractor (as Denver does), or your financing requires a finished appraised home before funds release.

Table 7 — The decision matrix

Self-score each row. If you check three or more in the kit column without contradictions in the others, a kit deserves a serious look. If you check two or more in the turnkey column, look at finished prefab. If you check three or more in the site-built column, hire a local GC and skip the catalog entirely.

The pre-deposit seller checklist (20 questions)

Before you wire money to any kit seller, get these answers in writing. Sellers who can answer all 20 directly — without dodging — are the sellers worth working with.

1. Is this kit designed for permanent residential occupancy as an ADU?
2. Is it panelized, SIP, modular, manufactured (HUD-code), container-based, or another category?
3. What building code standard is it designed to meet (IRC, state-modified IRC, HUD)?
4. Are stamped architectural plans included? If not, at what additional cost?
5. Are stamped structural engineering calculations included?
6. Is energy-code documentation included, and for which climate zones?
7. Is the foundation designed and detailed, or only referenced?
8. Who handles the permit application and plan check?
9. Who handles local plan revisions if the city requires changes?
10. What’s specifically included: plumbing, electrical, HVAC, insulation, roofing, gutters, finishes?
11. Is shipping included? If not, what’s the typical cost to my zip code?
12. Is crane, forklift, or lift-gate delivery required for my lot?
13. Is installation included or is it a separate ProAssembly contract?
14. Are licensed trades included or do I need to hire them locally?
15. What is explicitly excluded? (Ask for the written exclusion list.)
16. What voids the warranty?
17. What happens if my city rejects the plans?
18. What portion of the deposit is refundable, and under what conditions?
19. Can the plan be modified for my city’s specific requirements?
20. Has this model been permitted as an ADU in my state or city before? Can you provide a reference?

The five most common backyard ADU kit mistakes

Watching these patterns repeat across homeowner stories is how we learned to write this guide. All five are avoidable with five minutes of preparation.

Mistake 1: Comparing kit sticker prices to turnkey installed prices. A $52,691 Studio Shed shell and a $278,800 Abodu Studio are not competing products. The first is a starting point; the second is a key-in-hand home with the foundation tie-in, finishes, and one-day install built into the number. Always compare all-in to all-in.

Mistake 2: Assuming “DIY” means “no permits.” Every kit still needs a full permit set in nearly every U.S. city. The DIY in DIY ADU refers to assembly labor, not to skipping municipal approval. Some cities — Denver among them — require a licensed contractor for ADU construction regardless of who owns the property.

Mistake 3: Buying before checking lot access for the delivery truck. A flatbed carrying large wall panels does not fit through a 6-foot side gate. Walk your property with a tape measure first.

Mistake 4: Forgetting permits and fees. Permit fees — and where applicable school-facilities and impact fees — aren’t listed on the kit page. California exempts many ADUs under 750 sq ft from impact fees, while larger units may owe more. Ask your city for the exact schedule for your unit size.

Mistake 5: Ordering the kit before the foundation contractor. The foundation goes first, the panels arrive next. Panels stored on a driveway for weeks because the foundation isn’t ready develop weather damage and storage fees. Sequence: city pre-application → plan check → foundation contract → kit order timed to foundation cure.

Frequently asked questions

What we verified for this update

For this guide, we verified:

• Kit and base-package prices directly from public retailer and manufacturer pages: Home Depot product listings for Studio Shed Summit 476A, Summit 800A, and Summit 800B; Home Depot listings for Bedrock Building Group steel-frame kits; Home Depot listing for PLuS1 Chill Out (305 sq ft, $22,999); Mighty Small Homes Modern kit pricing; Studio Shed / Studio Home finished Summit Series pricing; Modular Home Direct steel-frame model pages.
• Construction method and scope claims against manufacturer-published “what’s included” pages, including DC Structures’ published exclusion list and Studio Shed’s published finished pricing.
• Federal code references against the eCFR for 24 CFR Part 3280 (HUD manufactured housing) and the 2024 IRC Appendix BC (accessory dwelling units).
• Fannie Mae financing eligibility against Selling Guide B2-3-02 (factory-built housing classification) and B2-3-04 (ADU financing eligibility).
• City-specific ADU rules against official planning and building department pages for Portland, OR; Seattle, WA; Denver, CO; San Diego, CA; Charlotte, NC; Minneapolis, MN; and Austin, TX.
• California state law against the official Assembly Bill text for AB 68, AB 2221, and AB 2533.
• Comparison reference price for the Abodu Studio ($278,800 starting) from Abodu’s official model page.

What we did not independently verify (treat as illustrative until you confirm directly):

• The all-in finished cost ranges in Table 2 — these are illustrative national averages, not quotes for specific projects.
• Every city’s current ADU ordinance — only the seven listed above.
• Every state’s current ADU statute — for those, see our regulations hub.
• Each manufacturer’s current shipping cost to your zip code, and current promotional discounts on listed prices.

Methodology

The Dwelling Index is an independent research resource covering ADU financing, costs, and regulations. We do not sell ADUs, do not represent any single manufacturer, and do not rank providers by affiliate payout.

How we built this guide. We surveyed published kit prices, scope language, and exclusion lists from a representative cross-section of the backyard ADU kit market — including bare shells, insulated panelized shells, SIP kits, full-package kits, and modular base packages. We then normalized those prices against finished-cost ranges from manufacturer-published guidance (notably Studio Shed’s own finished pricing and DC Structures’ published 3×–5× multiplier rule), regional ADU builder published ranges, and national cost data from HomeGuide and Neighbor.com. City permit treatment was verified against each city’s official planning or building department page on the date listed in “What we verified.”

What we mean by “kit.” A panelized, pre-cut, SIP, or modular base package shipped flat or in modules for on-site assembly. We exclude purely turnkey factory-finished prefabs (see our prefab ADU cost guide) and HUD-code manufactured homes.

What we did not do. We did not fabricate reviews, ratings, or testimonials. We did not rank kits “best to worst” by commission — kits are presented by category and price for transparency. We did not include partners on this page where their service area does not match a national informational query.

Editorial judgments labeled as such. Where we draw a conclusion about who a kit is right for, we present it as our research-based view, not as objective fact. Code, financing, and regulatory claims are sourced to primary documents.