ADU Builders in Highland — Plans, Permits & Build, One Fixed Price

Trusted ADU Builders for Highland Homeowners

If you’re trying to figure out how to add a rental unit, an in-law suite, or extra living space on your Highland property, the real question isn’t whether an ADU makes sense. It’s how to avoid paying for the wrong build method, the wrong design, or a contractor who treats your project like a side gig. That’s where Highland ADU Builders like Sunburst comes in. We’re led by Noel Carrasco, and we focus on one thing: matching Highland homeowners to the right ADU, whether that’s a prefab unit from Cover or Dvele, a Boxabl, a custom stick-built, or something in between. Call us at (855) 676-6807 and we’ll walk you through the fit for your lot.

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ADU Construction

ADU Construction in Highland is the full process of building a legal secondary dwelling unit on your property, from grading and foundation through framing, utilities, drywall, and final finishes. Most Highland homeowners pursue this for rental income or to house aging parents, and the cost typically lands between $180,000 and $350,000 for a turnkey detached unit, with JADUs running lower and larger custom builds running higher. At Sunburst, we handle the entire build sequence under one contract, so you’re not coordinating a foundation crew, a plumber, and a cabinet installer yourself.

Foundation and Site Work

Highland’s soil, particularly in the older East Highland neighborhoods, often has expansive clay that moves with moisture changes. We start every project with a proper compaction and drainage plan so your ADU doesn’t develop cracks in year two. The driveway and utility trenching get scheduled together to avoid tearing up your yard twice.

Framing Through Finish

Once the foundation is inspected, framing moves fast, usually three to five weeks for a standard unit. After that, rough-in plumbing and electrical, insulation, drywall, and then the finishes you actually see every day. Because we also do kitchen and bathroom remodeling, the interior of your ADU gets the same attention as a primary-home renovation, not builder-basic closings.

Detached ADU

A Detached ADU is a free-standing unit built in your backyard, completely separate from the main house, which gives you full rental privacy and the highest per-square-foot rent of any format. In Highland, a detached unit with a kitchen and bath typically costs $200,000 to $380,000 depending on square footage and build method. Sunburst ADU Builders delivers detached units across prefab, panelized, and custom stick-built approaches, so you get a real comparison of cost and timeline before you commit.

Prefab vs. Custom Detached

Prefab units from builders like Cover and Dvele often trim months off the schedule because the modules are built in a factory while we prep your site concurrently. Custom detached builds give you exact floor-plan control and are the better path on odd-shaped lots. We’ll show you line-item pricing for both before you sign anything.

Setbacks and Lot Coverage

Highland enforces standard California ADU setbacks, typically four feet from side and rear property lines for detached units, but corner lots and narrow parcels get tricky. We check your lot dimensions against current city rules before you spend a dollar on design, so you don’t fall in love with a plan that can’t be permitted.

JADU

A JADU, or Junior Accessory Dwelling Unit, is a conversion of existing space inside your home, usually a garage or a spare bedroom, into a compact independent unit of 500 square feet or less. This is the fastest and least expensive path to a legal rental in Highland, often running $80,000 to $160,000 depending on the bathroom addition and kitchenette scope. Sunburst ADU Builders handles JADU conversions with the same permit discipline we apply to full detached builds.

Garage Conversions

Converting an attached garage into a JADU is popular in Highland because the structure already exists. The main costs are insulation, a bathroom, a kitchenette, and separate egress. We preserve the existing footprint where possible to keep the budget down, but we’ll be straight with you about when the slab or electrical panel isn’t up to code.

Interior Unit Conversions

A spare bedroom or bonus room can become a JADU with a private entrance and a small kitchen. The challenge is usually plumbing access for the bathroom. Because we also do bathroom remodeling, our crew can run drain lines and install fixtures without tearing apart more of your house than necessary.

ADU Plans

ADU Plans are the architectural drawings and engineering documents required to get your building permit from the City of Highland, and they’re the single most common source of delay for homeowners who try to go it alone. Sunburst ADU Builders produces or coordinates complete plan sets, including site plans, structural calculations, and title 24 energy compliance, as part of every project. Plan costs typically run $4,000 to $10,000 depending on complexity and whether we’re working from a prefab manufacturer’s standard set.

Working With Manufacturer Plans

Prefab manufacturers like Boxabl and Mighty Buildings provide engineered plans for their units, but the site-specific work, your foundation, utility runs, and setbacks, still has to be done locally. We adapt their drawings to Highland’s specific requirements rather than hoping the city accepts a generic set. That’s the difference between a three-week permit and a three-month resubmission loop.

Custom Plan Development

For custom stick-built or shed-conversion projects, we work with licensed drafters and structural engineers who know Highland’s review process. Every plan set includes drainage, grading, and fire-access notes specific to your parcel. You’ll see the same drawings the city sees, and we’ll walk you through them in plain English before submission.

ADU Contractor

An ADU Contractor is the licensed professional responsible for pulling permits, managing subcontractors, scheduling inspections, and delivering a completed unit that passes final sign-off. In Highland, hiring the right ADU contractor matters more than your choice of floor plan, because a bad build sequence can add months and tens of thousands in rework, which is why our ADU Builders Troubleshooting: Common Problems and How to Fix Them approach starts with prevention. Noel Carrasco and the Sunburst team work as your single point of accountability from pre-construction through final inspection.

Why Manufacturer-Agnostic Matters

Most contractors in Highland either build only stick-frame, or they rep a single prefab brand and pitch you one product. We’re not tied to any single manufacturer. We’ve built with Cover, Dvele, Boxabl, and others, and we’ll tell you honestly when a custom build is cheaper than prefab for your site, and when it isn’t.

One Contract, Full Scope

Your ADU needs a kitchen, a bathroom, flooring, paint, and lighting to be rentable. We do all of it internally, no handoff to a separate remodeler. That means your warranty isn’t split across two companies arguing about who ran the drain line wrong. One phone number, one team, one name on the contract.

ADU Design

ADU Design is the process of shaping your unit to fit your lot, your budget, and your intended use, whether that’s a studio for rent, a two-bedroom for family, or a workspace with a bathroom. Sunburst ADU Builders approaches design as a cost-control exercise first and an aesthetic conversation second, because a beautiful plan you can’t afford to build is just a drawing. Design fees in Highland typically run $2,500 to $8,000 as a standalone service, and are often folded into the total build contract.

Design-to-Budget Discipline

We start every design conversation with your hard numbers, total budget, target rent, timeline. Then we work backward into square footage, kitchen scope, and finish level. Choosing James Hardie fiber-cement siding at the design stage, for instance, adds upfront cost but eliminates paint cycles and keeps the unit looking sharp for years of tenant turnover.

Lot-Specific Layouts

Highland lots vary widely, from the flat, wide parcels north of Baseline to the tighter hillside lots around the eastern edge of town. We orient windows for light and privacy against your neighbors, position the entrance for tenant access without crossing your backyard, and place the mechanicals where they won’t hum through a bedroom wall.

Backyard ADU

A Backyard ADU is any detached living unit built in the rear yard of your property, and it’s the most common format Highland homeowners choose because it maximizes rental income while keeping the main house private. Expect a typical backyard unit with one bedroom, one bath, and a full kitchen to cost $220,000 to $350,000 in this market. Sunburst ADU Builders has delivered backyard ADUs across every build method currently viable in California.

2D vs. 3D vs. Prefab for Backyards

If your yard has tight access from the street, a Mighty Buildings 3D-printed panel system or a Boxabl foldable unit can get materials to the site when a full modular section won’t fit. If access is wide open, a full factory-built module from Cover saves the most time. We’ll walk you through the access constraints first, because they narrow the realistic options faster than anything else.

Rental-Ready From Day One

A backyard ADU in Highland only pays off if it’s legally rentable and actually rented. That means a proper kitchen, a full bath, its own address, and separate utilities. We build every unit to qualify for a certificate of occupancy and, where appropriate, separate metering. Then our kitchen and bathroom remodeling crews finish the interior to a standard tenants will pay for, not a standard they’ll tolerate.

Brands We Service

Sunburst ADU Builders works with a curated roster of prefab and modular manufacturers, not because one is best, but because different lots and budgets call for different engineering. With Cover, we use their precise factory-built modules when access allows and the schedule matters. With Dvele, we lean on their high-performance panelized envelope for homeowners who want a unit built to outlive the primary house.

Mighty Buildings and Boxabl are the two we turn to when site access is tight, a narrow side yard, a steep driveway, or utility lines that pinch the crane zone. Their panel and foldable designs fit where full modules can’t, and we handle the local site prep and finishing so their engineering lands correctly on Highland soil. Whether you already own a prefab shell or you’re weighing a specific manufacturer against custom, we can help you compare before you commit.

Signs You Need a Pro Right Now

• Your lot has a drainage problem that’s killing your build timeline. Highland’s summer thunderstorms and the occasional winter downpour turn a low corner of the yard into a permit problem. If water pools where your ADU’s foundation will sit, the city will flag it. We fix the grade and drainage before the concrete goes in.
• You’ve been told different things by three different prefab companies. One says their unit is ready in six months, another says permits are the client’s problem, a third won’t return calls. That confusion means you need a manufacturer-agnostic contractor who can compare the actual options against your lot and budget.
• Your garage has foundation cracks or an old fuse panel. A JADU conversion assumes the existing structure can handle it. If your garage floor is spalling or your electrical service is from the 1950s, you need a pro to tell you what’s salvageable and what has to be replaced before the city will sign off.
• Your side-yard access is under 8 feet wide. That number eliminates most crane-delivered modular units from the list. If you’ve already paid for plans that assume full module delivery, you need a contractor who knows which panelized or foldable systems actually fit through the gap.
• You’re trying to manage the permit process yourself and the city keeps bouncing it. Highland’s building department has specific requirements for ADU submittals, and a resubmission loop costs you weeks each cycle. A contractor who submits local plans daily knows what the reviewers look for and fixes it before the first rejection.

Our Process, Step by Step

1. 1
   Site Review and Feasibility Call. We walk your property in person or by video, look at access, setbacks, utilities, and grade, and then tell you honestly whether a detached, attached, or JADU makes sense. You leave this step with a realistic budget range, not a sales pitch. Call (855) 676-6807 to start here.
2. 2
   Build-Method Comparison. We price out your project across at least two, usually three, build methods: full prefab module, panelized or 3D-printed system, and custom stick-built. You see the cost, timeline, and trade-offs of each in writing before any design work begins.
3. 3
   Design and Plan Development. Once you pick a direction, we produce or adapt the plan set for Highland’s specific requirements: setbacks, drainage, title 24 energy, fire access, and structural calcs. You review and approve every drawing before it goes to the city.
4. 4
   Permitting and Pre-Construction. We submit your plans, handle the review corrections, and pull the permit in our name. While the city reviews, we order long-lead materials and schedule subs, so the build starts the week approval comes through.
5. 5
   Build, Finish, and Hand Over. Our team constructs the shell, our kitchen and bathroom crews finish the interior, and we walk you through every room before final inspection. You get a completed, permitted, rentable unit and one warranty from one company.

How Much Does ADU Builders Cost in Highland?

Our Service Area Near Highland

Sunburst ADU Builders serves Highland and the surrounding Inland Empire communities, including San Bernardino, Redlands, Mentone, Loma Linda, Colton, Grand Terrace, Rialto, and the mountain communities like Running Springs, Crestline, and Lake Arrowhead. If you’re just starting your research, our home page has an overview of what we do and how we price. We’re a local team that knows these neighborhoods and their permit offices.

Frequently Asked Questions About ADU Builders in Highland

Schedule Your ADU Builders Service in Highland Today

You’ve done the research. Now get a straight answer from a team that builds ADUs every day in the Inland Empire. Call Sunburst ADU Builders at (855) 676-6807 to schedule your free, no-obligation site review and estimate. We’ll walk your property, compare your build options, and give you real numbers, not a sales script.

Written by Noel Carrasco, Owner at Sunburst ADU Builders, serving Highland since the company’s founding.