ADU Before & After in Hesperia, CA
We’ve designed, permitted, and built over 900 ADUs since 2015. Every project started with a written price and ended with a documented photo record. These before-and-after stories from Hesperia and the High Desert show what actually changes when you convert a garage, add a detached unit, or build a Junior ADU under one contract with one point of contact.
Recent Transformations
Garage Conversion ADU: Unused 2-Car to 480-Square-Foot Rental in Spring Valley Lake Area
The garage sat empty for three years after the homeowner stopped storing an RV. The slab was 4 inches thick, within range for conversion, but the existing electrical was a single 120-volt circuit feeding a workbench light. We pulled a new 200-amp service, added a 3/4 bathroom with a wall-hung vanity to preserve floor space, and ran a mini-split on a dedicated circuit. The city required a 5-foot side setback variance - we handled the variance application in the permit set rather than surprising the owner mid-project. Under Haven Standard Clause 1, the $87,500 all-in price was written before we touched the slab. The owner now rents it at $1,400 per month.
New Detached ADU: Backyard Build on Hesperia’s West Side With Abodu System
The lot was flat, which saved $4,200 in grading compared to the sloped sites we often see north of Ranchero Road. The client wanted speed without sacrificing the ability to customize finishes, so we specified an Abodu One module with upgraded LVP flooring and a tile shower surround we sourced locally through our James Hardie supplier. We handled the foundation, utility trenching, and final tie-ins under the same contract - no separate general contractor to coordinate. The photo record shows every phase: the pier pour, the crane set, the rough electrical inspection, the final. Total project time from permit submission to certificate of occupancy: 11 months. Written price at signing: $184,000.
Junior ADU & Interior Conversion: Splitting a 1,850-Square-Foot SFR in Oak Hills
The owner needed to house her mother but couldn’t justify a detached build on a 6,000-square-foot lot with limited backyard depth. We converted the front formal living room - 420 square feet that saw three hours of use per week - into a Junior ADU with a kitchenette, 3/4 bath, and separate exterior door. The key challenge was the sound-rated wall assembly between the JADU and the main residence; we used resilient channel and two layers of 5/8-inch Type X with Green Glue, documented in the photo record so the inspector could verify without opening walls. The JADU shares the main home’s meter per California’s owner-occupancy JADU rules, which kept utility costs down. Written price: $52,000. No change orders.
ADU Site Prep & Utilities: Grading and Trenching for a Dvele Module on the Mesa
This lot had two problems: a 12-foot elevation change from the street to the buildable area, and granite shelf at 18 inches that standard trenching equipment couldn’t penetrate. We brought in a trackhoe with a hydraulic breaker for the rock, poured a 6-inch reinforced retaining wall to create a 24-by-32-foot pad, and trenched 85 feet for sewer, water, and electrical to the main house connection points. The Dvele module arrived eight weeks later on a flatbed; our crew handled the crane set and final utility tie-ins. The site prep contract was separate from the module purchase but under the same Haven Standard terms - written price, photo record, no surprises. Site prep only: $34,500.
Garage Conversion ADU: Attached 1-Car to Accessible Studio Near Hesperia Lake
The homeowner’s father was moving in after a hip replacement and couldn’t navigate the main house stairs. The attached 1-car garage had a 7-foot-6-inch ceiling and a 4-inch step-down from the kitchen - both fixable, but both requiring early decisions. We excavated 18 inches for a zero-threshold entry and reframed the ceiling with scissor trusses to gain 18 inches of headroom, then ran a 36-inch door path through the former garage door opening with a ramped transition to the driveway. The roll-in shower with grab-bar blocking was documented in the photo record before tile went up, so the inspector verified blocking placement without destructive testing. All-in with accessibility upgrades: $96,000, written at the first site walk.
New Detached ADU: Custom Stick-Built on Sloped Lot Near Summit Valley
The slope was the story here. A 15-percent grade with a seasonal drainage channel running diagonally across the buildable area meant standard slab-on-grade was out. We designed a pier-and-grade-beam foundation with eight piers drilled to 6 feet, then built a 620-square-foot two-bedroom stick-framed unit with a 120-square-foot deck suspended from the same pier system. The drainage challenge was real - we installed a French drain collection system tied to the city’s storm inlet, permitted through San Bernardino County’s floodplain review because the channel carried enough flow to trigger their threshold. The photo record includes every pier pour with rebar placement visible, every drainage layer before backfill, and every inspection sign-off. This was not a prefab candidate given the site constraints, so we self-performed the build. Written price: $217,000. The owner hosts short-term renters now; the deck faces southwest toward the Cajon Pass.
Want Results Like These?
Every project on this page started the same way: a site walk, a written price, and a single contract covering design, permitting, and construction. No designer blaming the builder. No builder blaming the designer. If you’ve got a written estimate from another firm, we’ll give you a free second opinion - no obligation, no pressure.
Call (760) 493-7752 to schedule your free estimate. A live person answers, 24/7.
Written by Nadia Ellery, Owner at Ellery ADU Studio Hesperia, serving Hesperia and the High Desert since 2015.