The detached garage on this Lake Elsinore lot was a 24 ft × 24 ft box that held nothing but storage bins and an old workbench. Its slab was sound, the roof still serviceable, and the structure already sat the required 10 ft off the rear property line. Those three facts shaped every decision that followed: keep the existing footprint, avoid foundation work, and steer clear of setback drama. The owner’s brief was just as clear—turn it into a legal 1-bed/1-bath ADU for about $100 k in construction and under $8 k in city fees.
GatherADU began with a forensic walk-through to spot hidden cost traps. Electrical service was only 100 amps, but household load history showed enough headroom for a 60-amp sub-panel in the ADU. Sewer access lay fifteen feet from the garage wall, a distance short enough to avoid a costly ejector pump. The slab sat a full foot above grade, already clearing finish-floor height rules. Each confirmation shaved risk off the budget before plans were even drawn.
The architect’s answer to a tight footprint was a layout that stacks plumbing, maximizes daylight, and wastes zero inches on circulation:
Passive-solar logic governed window placement: larger units on south and east, smaller on west, none on north. The result is a bright interior that stays cool after noon.
Lake Elsinore treats garage conversions as remodels, so existing framing can stay if it meets code. The original 2×4 studs at 16 in o.c. did. That instantly saved a full re-sheath. A structural engineer’s letter confirmed the 4-in slab could handle new loads, avoiding any under-slab retrofit.
GatherADU submitted a complete first package—architectural sheets, structural letter, Title 24 calcs, and a waste-management plan. Because the design kept conditioned space under 500 sq ft, impact fees dropped dramatically. Plan check comments were trivial: mark smoke-alarm locations, temper one bath window, confirm lever-handle door hardware. A single resubmittal closed them out, and the permit arrived four weeks after the initial filing.
Final fee tally: $7,796, landing neatly inside the owner’s $8 k cap.
Selective demo came first: roll-up doors, shelves, and the obsolete workbench were gone in two days. The plumber cut narrow trench lines only where new pipes crossed the slab, filling them with slurry for traceability. A 12k-BTU mini-split would handle all heating and cooling. Electrical ran in EMT along the bedroom wall straight into that 60-amp sub-panel—short, direct, cheap.
Outside, the team skinned the garage in vertical Hardie Panel with 1×2 battens. Panels fastened straight to studs, skipping OSB and its labor. A light sandstone paint sealed the look. Clay-tone vinyl windows hit Title 24 U-factors without the price tag of aluminum clads.
Inside, finishes balanced economy and longevity:
Weekly site walks hammered punch-list items early—an out-of-plumb window, a receptacle that should be GFCI, one smoke detector moved three inches. Final inspection passed on the first call. Three days later the certificate of occupancy was in hand.
Biggest cost lines? Finish carpentry and cabinets (nearly 25 %), MEP trades (20 %), and framing/insulation (15 %). The rest went to siding, roofing, and a mini-split that will outlive a decade of tenants.
Step inside and the volume surprises people. Vaulted ceilings peak at 10 ft 6 in, and there’s a clean sight-line from the living room window all the way into the bedroom. Morning sun pours across the vinyl planks; by afternoon the low-E glass and roof insulation keep things cool. The bedroom fits a queen bed, two nightstands, and a six-foot mirrored closet that visually doubles the width. The kitchen island hosts work-from-home laptop hours and dinner for two. In the bathroom the barn door never blocks a pathway, and that stacked washer-dryer sits behind another pocket door, silent until laundry day.
Structural letters, prescriptive framing, Title 24 compliance—they all went in before the first submittal. In a region desperate for attainable housing, this project shows what’s possible: convert underused space, respect a six-figure budget, meet code the first time, and deliver a bright, durable home without expanding the urban footprint.
GatherADU handled the process end-to-end—planning, permits, and build. If you own a tired garage and a tight budget, the path is clear and repeatable. Sound slab, concise plans, disciplined execution. That recipe just added one more legal dwelling to Lake Elsinore, and it can do the same for you.
Explore your ADU possibilities with Gather. We provide ADU planning, design, permitting, and construction management services in California, Georgia, Washington, Oregon and beyond!
