Frequently Asked Questions - ADU in Highland, CA
Straight answers to the questions Highland homeowners ask us most about accessory dwelling units. If you don't see your question here, call (855) 676-6807 and we'll talk it through.
Pricing & Cost FAQs
An ADU in Highland typically runs from $150,000 to $350,000 depending on size, site conditions, and finishes. A detached 2-bedroom unit with standard finishes usually lands between $180,000 and $250,000, while a garage conversion runs lower, often $120,000 to $180,000. Costs shift based on slope, soil, utility distances, and whether you choose a custom build or a prefabricated system. The only way to get a real number for your property is a site visit. Call (855) 676-6807 to schedule your free estimate, and we'll give you a written line-item quote before any work begins.
Expect to pay between $300 and $500 per square foot for a detached ADU in Highland. Attached units and garage conversions often come in at $250 to $400 per square foot. The lower end assumes standard materials and a simple foundation. The higher end reflects steep grades, upgraded kitchens, higher-end windows, and custom exterior finishes that match the main house. Prefabricated systems from manufacturers like Dvele or Boxabl can narrow that range because factory production removes some site labor. Your final number depends on your lot. We provide a fixed, line-item price after a free on-site assessment, so you know exactly what you're paying before you sign.
No. Estimates are free. We walk your property, discuss what you want, check access, slope, and utility locations, then put together a written, line-item quote. There is no charge for any of this, and no obligation. You keep the quote either way. The only time costs arise is if you ask us to produce full construction drawings from an architect, and we'll tell you that cost upfront before any design work starts. If you're comparing ADU builders in Highland, get at least two written estimates. Then call (855) 676-6807 and let us show you how our pricing holds up.
It should not, provided the scope does not change. We quote a fixed price with a line-item breakdown, and we do not use open-ended allowances. If San Bernardino County inspectors require something unforeseen, or you change finishes mid-build, we'll put the change in writing and get your sign-off before proceeding. What you won't get is a surprise bill at the end for things we should have caught in planning. The best protection against price creep is a detailed plan and a builder who walks the site before quoting. Our written quote reflects the actual conditions on your Highland lot, not a guess.
ADU permit fees in Highland and San Bernardino County generally run from $3,000 to $8,000 depending on the project size and whether impact fees apply. State law limits some fees on ADUs under 750 square feet, but school district fees, water and sewer connection charges, and plan check fees still vary by jurisdiction. Highland homeowners should budget for the permit package as a separate line item from construction. We pull all permits ourselves, and the permit costs appear clearly in your quote. Call (855) 676-6807 if you want us to walk through the permit costs for your specific parcel.
A garage conversion in Highland typically costs between $120,000 and $180,000. Conversions are cheaper than new detached units because the structure, roof, and foundation often already exist. You still pay for insulation, drywall, electrical, plumbing, windows, and a new bathroom and kitchen. Some older Highland garages have slabs too thin for habitable space, and that can add foundation work. We inspect the existing structure before quoting so your number reflects what's actually there. If you're pricing a conversion, call (855) 676-6807 and we'll give you a real quote based on your garage, not a generic range.
Service & Process FAQs
The process is site evaluation, design, permits, construction, and final inspection. We start with a free site visit to assess your lot, access, and utility connections. Then we design the unit with you, submit plans to the City of Highland or San Bernardino County, pull permits, and build. Construction usually takes 6 to 12 months from permit approval to final. You'll get a schedule, a dedicated point of contact, and regular updates. We handle every permit and inspection. Your job is to make design choices and watch the progress. Call (855) 676-6807 to start with a free site evaluation.
Yes. Highland has its share of sloped and hillside lots, especially in the East Highlands area, and we build on grade changes regularly. Sloped lots usually require retaining walls, stepped foundations, or pier-and-beam systems, which adds cost and engineering time. The soil in this part of the Inland Empire often has expansive clay, so foundation design matters more than on flat land. We bring in a soils engineer when the grade warrants it, and that report shapes the foundation plan. A sloped lot doesn't rule out an ADU. It just means the site assessment matters more. Call (855) 676-6807 to have us look at your grade.
We handle the entire build. Design coordination, permits, foundation, framing, electrical, plumbing, HVAC, drywall, finishes, and final inspection. You won't be hiring separate trades or coordinating schedules. We manage the subcontractors and hold them to a written scope of work. The benefit for a Highland homeowner is one point of contact and one contract. If you need something outside our scope, like solar or landscape drainage, we'll tell you early and can coordinate with whoever you bring in. The build is ours to complete. Call (855) 676-6807 to talk about your project scope.
Plan on 6 to 12 months for a detached ADU in Highland, from the day permits are approved to final inspection. Garage conversions run faster, often 4 to 8 months. The big variables are plan check times at San Bernardino County, weather windows, and any site work like retaining walls or utility trenching. Prefabricated units can compress construction significantly because panels or modules arrive on site ready to assemble. We give you a schedule with real dates after the permit is issued, and we update it as work progresses. Call (855) 676-6807 and we'll give you a realistic timeline for your lot.
Yes. Many Highland homeowners build ADUs specifically for rental income, and units here rent well given the demand from Redlands and Loma Linda workers who want to stay near the hospitals and university. We design for durability and low maintenance, which matters when tenants occupy the space. We'll also confirm that your intended use, long-term rental, complies with local short-term rental rules if that's your plan. Your return depends on your build cost and the local rental market, which we can help you think through. A well-built ADU rents reliably in this area. Call (855) 676-6807 to discuss building for income.
Yes, and that's a common arrangement in Highland. Homeowners move into the smaller, newer unit and rent the main house, often covering a large share of the mortgage. Zoning allows this, provided the ADU was built with proper permits and meets the owner-occupancy requirements in effect at the time of permitting. Check with the City of Highland on current owner-occupancy rules, since state law has shifted on this in recent years. We build the units to code, and the rest is a rental property decision. Call (855) 676-6807 if you want to talk layout and design for living in the unit yourself.
Brands & Parts FAQs
We have worked with prefabricated systems, and manufacturers like Boxabl and Dvele are legitimate options for Highland homeowners who want factory-built precision. Prefab can compress the on-site construction timeline because the modules or panels arrive partially or fully assembled. Site work, foundation, utilities, and finish connections still happen on site, and that's where our crew comes in. The right system depends on your lot access, your design goals, and your budget. We are happy to discuss these options during a free estimate and help you compare them to conventional framing. Call (855) 676-6807 to weigh the options.
The Inland Empire gets real heat, with summer days regularly over 100 degrees in Highland, so insulation and window orientation matter more than the building method. Standard wood framing works well when insulated beyond code minimums and paired with high-quality windows. Prefabricated panels from companies like Dvele often arrive with tighter tolerances and better air sealing than site framing. The bigger decision is the building envelope, not the frame. We size HVAC for the actual heat load, not a rule of thumb, because a poorly cooled ADU in East Highlands is miserable by August. Your method should follow your goals and budget, not a trend.
We're brand-agnostic. We've built with conventional framing and we've worked alongside prefab systems, and each has its place. The right choice for a flat lot in North Highland with good truck access is different from a tight hillside parcel in East Highlands. We prefer to make that call with you after we've seen the site. What we won't do is push a brand that doesn't fit your budget or your property. If you have a manufacturer in mind, we'll work with them. If you don't, we'll lay out the options straight. Call (855) 676-6807 to talk through the pros and cons.
Licensing & Insurance FAQs
Yes. Sunburst ADU Builders operates with the licensing and insurance required for residential construction in California, and every pro working under our name is required to hold the license and insurance their trade requires. We carry general liability coverage and we pull permits on every project we build in Highland. You should verify license status on any contractor you consider, and we're happy to provide our documentation before you sign. A permitted, inspected ADU protects your property value and your insurance coverage. Call (855) 676-6807 and we'll share our credentials with you directly.
We do. Permits are not optional on ADUs, and we handle the full package: plan submission, plan check, revisions, and every inspection through final sign-off. Building without permits in San Bernardino County can trigger fines, forced removal, or an unpermitted structure that clouds your title when you sell. We've seen enough unpermitted additions to know it's never worth the short-term savings. Our contracts include the permit work as part of the job. You'll see permits as a line item in your written quote, and we manage the process end to end. Call (855) 676-6807 to ask about permitting for your project.
It typically does. You'll want to update your policy once the ADU is complete, because the replacement cost of the property has increased. Some insurers also want to know if the unit will be rented, since landlord situations carry different liability. Let your agent know during construction, not after the final inspection, so there's no gap in coverage. The good news is that a permitted, inspected, code-compliant ADU is viewed as a standard addition by most carriers. It's the unpermitted work that creates insurance headaches. Ask your insurer, and call (855) 676-6807 if you need documentation for them.
Emergency & Response FAQs
First, protect the interior. Move belongings, place buckets, and if water is coming through a light fixture, shut off that circuit at the breaker panel. Then call us at (855) 676-6807. We respond during our business hours, Monday through Friday from 7:00 AM to 7:00 PM and Sunday from 7:00 AM to 7:00 PM. Highland's winter storms can be intense, and the East Highlands area catches more rain than the valley floor. We'll assess the leak, identify the source, and make a repair plan. Until we arrive, do what you can to minimize interior damage. Roof leaks get worse fast when ignored.
Yes. We build to current California Building Code, which includes roof drainage and flashing standards designed for real rain events like the ones Highland gets in winter. We flash every roof penetration thoroughly, use proper underlayment, and slope flat areas correctly. The bigger point is inspection. Every part of the roof and drainage system is inspected before the final sign-off, so you're not relying on trust. We also recommend gutters sized for local rainfall, especially on the east side of town where the terrain funnels water. A new ADU built to code is a dry building. Call (855) 676-6807 to talk roof specifics.
We answer the phone Monday through Friday from 7:00 AM to 7:00 PM, and Sunday from 7:00 AM to 7:00 PM. Saturdays we're closed. When you call, a live coordinator answers and connects you with the local team working in Highland and the surrounding Inland Empire cities. If you reach us outside those hours, leave a message and we'll get back to you on our next business day. For questions about an existing project, your point of contact is available during those same hours. Call (855) 676-6807 anytime during business hours and a real person will pick up.
Warranty & Guarantees FAQs
Yes. We stand behind our workmanship with a written workmanship warranty, and we pass through all manufacturer warranties on materials, fixtures, and appliances used in your ADU. The specific terms depend on the scope of your project, and they're spelled out in your contract before you sign. What matters is that we're not hard to reach after the final check. You can call the same number, reach a real person, and get a response. A warranty is only as good as the company behind it. Call (855) 676-6807 and we'll explain exactly what coverage your project includes.
The workmanship warranty covers defects in our construction labor, such as framing issues, drywall cracks beyond normal settlement, or improper installation of fixtures we installed. It does not cover normal wear and tear, damage from misuse, or issues caused by outside factors like shifting soil or extreme weather. Manufacturer warranties cover products separately, and we'll give you all the documentation for every product in your build. The warranty details are in your contract, in plain language, before you sign. If something doesn't look right after we finish, call (855) 676-6807 and we'll come look.
The standard workmanship warranty term is one year from the date of completion, and some structural elements may carry longer coverage depending on the specific scope. We'll put the exact term and what it covers in your contract before construction starts, so there's no ambiguity. Many material and appliance manufacturers extend warranties well beyond that, and we transfer all of that documentation to you at project close. The point is simple: if we made a mistake in our work, we fix it. Call (855) 676-6807 and ask us about warranty terms for your specific ADU project.
Hire a professional. This isn't gatekeeping; it's a realistic assessment of what an ADU involves. A legal ADU in Highland requires structural engineering, electrical and plumbing design, HVAC sizing, energy code compliance, and a series of inspections. A homeowner acting as owner-builder takes on liability, plan check, and quality risk that most people don't anticipate. We've fixed owner-builder projects that passed inspection on paper but had real problems inside the walls. If you want to save money, the better path is getting multiple written quotes and choosing a builder who communicates clearly. Call (855) 676-6807 and we'll show you what a professional estimate looks like.
Written by the team at Sunburst ADU Builders, serving Highland and the surrounding Inland Empire since 2018.
Still Have Questions?
We are happy to help. Call us — same-day and after-hours emergency service available.
(855) 676-6807