







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Garage Conversion Contractor Across Highland
A garage conversion in Highland typically runs $95,000 to $185,000 for a full apartment with kitchen and bath, or $55,000 to $85,000 for a simpler living space without plumbing. Permits move through San Bernardino County Building and Safety, not a city department, and parking replacement rules often shape the design before anything gets framed. We’re Fielding ADU Builders, and we’ve handled enough Highland garage conversions to know where the real cost drivers hide – the slab, the panel, the sewer line, and that parking clearance the County keeps asking about. Call (361) 315-4177 and we’ll price yours in writing before any work starts.
Here’s what matters: we put the number on paper before a single nail gets driven. We pull the permits, schedule the inspections, and stand behind the finished work for a full year under The Garrison Standard. If something fails inside that year, we come back and fix it at no charge. You won’t find that promise in most Highland bids.
Why Fielding ADU Builders Is Highland’s Preferred Garage Conversion Contractor Company

Highland homeowners call us because we understand what happens when a 1960s tract home in the unincorporated County zone opens up for a garage conversion. Reed Calloway runs our operation, and he built the process around one rule: price it honestly, build it by the book, and don’t leave a mess behind. The Garrison Partners network has held itself to that standard since 2006, and we’re the ADU and garage conversion arm inside that family.
Our crew shows up in uniform, background-checked and accountable. You’ll know exactly who’s walking onto your property near Base Line, Del Rosa, or East Highlands Ranch. No subcontractor roulette. No mystery pickups idling at the curb. When we say we’ll be there Tuesday at 7, that’s what happens.
And when you call at any hour, a live person picks up. Twenty-four hours a day, seven days a week. No voicemail tree, no callback queue. That matters when you’ve got a County inspector asking about your parking plan at 4:45 on a Friday and you need an answer before close of business.
Garage Apartment Conversion in Highland
A garage apartment conversion in Highland turns your existing attached or detached garage into a rentable dwelling with its own kitchen, bath, sleeping area, and usually a separate entrance. This is the highest-value conversion you can do, and it’s also the one most likely to hit County code snags. We recently converted a two-car attached garage on a 1960s tract lot near Base Line and Del Rosa into a one-bedroom garage apartment using James Hardie siding and a mini-split system. The job started with verifying the existing slab could handle the new plumbing and framing loads. The homeowner wanted a kitchenette and full bath, which meant trenching from the house to tie into the sewer and upsizing the panel to carry the added circuits. After County inspections cleared framing, electrical, and final, we delivered a permitted, rentable unit that kept a covered carport in the driveway to satisfy parking.
Slab and sewer reality
Highland garages built in the 1950s and 1960s often sit on slabs that were poured for parked cars, not for bathrooms. A 3-inch slab won’t pass for a plumbed living space. You may need an overlay, or in some cases a partial re-pour. And if the sewer line from the house can’t handle an additional bathroom group, you’re trenching to tie in – that’s where bids from contractors who didn’t check first start moving.
Panel capacity counts
A garage apartment with a kitchenette, bath, and mini-split needs real amperage. Many older Highland panels are 100-amp or less. The added circuits for the apartment will likely force an upgrade to 200-amp service, and that upgrade needs to be in the written price before you sign. We check this in the estimating visit, not after framing starts.
Garage Conversion Permit in Highland

A garage conversion permit in Highland goes through San Bernardino County Building and Safety because Highland sits in the County’s unincorporated sphere of influence. The County reviews plans, issues the permit, and sends inspectors for framing, electrical, plumbing, and final sign-off. The parking angle is the one that stalls most Highland projects: many parcels were subdivided in the 1950s and 1960s as single-family tracts with attached or detached garages, and the County often requires the conversion to retain a covered parking space or demonstrate legal parking under the current ordinance. That might mean a carport, a new covered structure, or a site plan showing two legal open spaces.
The sequence we run
We start with a zoning and parking review before we draw anything. Then architectural plans, structural calcs for the garage door header and any new openings, and the permit application package. Once the County approves and issues, we schedule inspections as the work progresses. You don’t chase inspectors; we coordinate all of it.
What holds approvals up
Skipping the parking-replacement check in the County zoning review is the most common reason a permit stalls or a final won’t sign off. The converted garage left the property without the required covered space, and now the whole project stops. We check that first, not last.
Trusted Brands We Service in Highland
We work with the prefab and modular systems Highland homeowners are already researching, including Garage Conversion Contractor options built around Abodu, Cover, and Dvele platforms. For conventional builds, we spec James Hardie siding and Tuff Shed-style structures where they fit the budget and lot. We keep the common trim, flashing, and siding profiles for Highland’s older tract homes on hand, which means fewer trips off the hill and faster turnarounds when the weather window closes in winter.
Common Garage Conversion Contractor Problems We See in Highland Homes
- Slab too thin for the new bathroom. The original garage slab was poured for cars, not plumbing. We hit this on most Highland garage apartments and budget for the overlay or re-pour from the first estimate, so it’s in the price, not a surprise later.
- Parking clearance kills the design. The County requires covered or legal parking in many Highland conversions. If the plan doesn’t show it, the permit stalls. We solve that on paper before demo starts.
- Garage door header becomes structural steel. That wide opening under the garage door often lacks a proper header for a wall and window infill. It’s a beam and posts job, and it needs to be in the bid.
- Panel and sewer capacity get ignored until after framing. A full kitchen and bath pull more power and produce more waste than the original house was built for. We check both in the first visit, before you sign.
Pricing for Garage Conversion Contractor in Highland, CA
A simple garage-to-living-space conversion in Highland, with drywall, insulation, flooring, lighting, and a mini-split, runs $55,000 to $85,000. A full garage apartment with kitchen, bath, separate entrance, and County-approved parking replacement lands between $95,000 and $185,000. The spread comes down to what’s inside the existing walls: slab condition, panel amperage, sewer depth, header spans, and whether the County wants a covered space added. We hand you a written price before any work starts, and that number is the number on the final invoice. The Garrison Standard is in writing: we stand behind workmanship for 365 days. If something fails, we return and correct it at no charge. Call (361) 315-4177 to schedule your free estimate.
We Also Serve Cities Near Highland
Our crews work throughout the Inland Empire, including San Bernardino, Loma Linda, Redlands, and Mentone. Same written pricing, same County permit handling, same one-year guarantee. If you’re near the Highland border, we’ll come scope it the same way we do here. Learn more about our work in Highland and the surrounding area.
Serving Highland, CA - Our Local Coverage Area
We’re based in the Highland area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Garage Conversion Contractor in Highland
Yes. Highland is in the County’s unincorporated sphere of influence, so San Bernardino County Building and Safety reviews plans, issues the permit, and runs inspections. The process involves a zoning and parking check first, then architectural and structural drawings, the permit application, and scheduled inspections for framing, electrical, plumbing, and final. We handle all of it. Call (361) 315-4177 and we’ll walk you through your specific lot.
It depends on what the County sees. If you keep the garage door in place and build a wall behind it, the space may not qualify as habitable because of daylight, ventilation, and emergency egress rules. Most Highland conversions remove the door and frame a wall with windows and a proper entrance. We’ll tell you what your house needs before you commit to a design.
Ideally, a recent survey or site plan, your current electrical panel amperage, and any records of past sewer work. If you don’t have those, we can pull what’s available from the County and the utility. We’ll also walk the garage with you to check slab, header, and access. That first visit gives us the numbers for a written price.
The usual movers are the slab thickness, the garage door header, the electrical panel size, and the sewer connection depth. We price these from a site inspection, so they’re in the original number, not added later. If the County requires a covered parking structure that wasn’t in the plan, that’s a change order, and we’ll price it in writing before we build it.
No. Garage conversions are permitted construction projects that need County review, inspections, and trades scheduling. A full garage apartment in Highland is typically a 8 to 14 week job from plan set to final inspection. We don’t promise same-week or emergency turnarounds because the work won’t pass inspection if it’s rushed. What we do promise is a real calendar and a written price. Call (361) 315-4177 for your free estimate.
Written by Reed Calloway, Owner at Fielding ADU Builders, serving Highland and the Inland Empire since 2006.



