ADU Before & After in Thousand Oaks, CA
Photos tell the truth that words can’t. Every project here started with a homeowner’s specific problem, a Thousand Oaks lot with real constraints, and a written price from us before anyone picked up a hammer. Scroll through what changed.
Recent Transformations
Garage Conversion ADU: Conejo Valley Single-Car to 420-Square-Foot Rental
The homeowner had a 1962 single-car garage in the Conejo Valley area with a 4-inch slab and no interior finish. Thousand Oaks allows garage conversions under SB 1069, but the existing slab needed a moisture barrier test, and the ceiling height was 7 feet 2 inches, below the 7-foot 6-inch living-space requirement. We designed a 6-inch drop in the bathroom floor and specified low-profile HVAC ducting to gain headroom without raising the roofline. The result is a 420-square-foot studio rented at $2,100 per month, permitted and inspected, with a separate electric meter the homeowner installed through Southern California Edison’s ADU fast-track program. Under Haven Standard Clause 1, the all-in price of $142,000 was written before we submitted the first permit drawing.
New Detached ADU: Lang Ranch Hillside with Septic Constraints
This Lang Ranch property sat on a 15-percent grade with a septic system sized for the main house only. The city required a perc test and a secondary leach field expansion before approving any additional bedroom count. We designed a 600-square-foot one-bedroom ADU with a composting toilet and graywater system that reduced the leach field load enough to avoid full replacement. The oak tree in the setback required a 6-foot radius protective barrier during construction, documented in our photo record at every visit. Total project from signed contract to certificate of occupancy: 11 months. The written price was $218,000 including the septic engineering, and it did not change.
Junior ADU: Newbury Park Attached Conversion with Shared Wall
The owners wanted housing for an aging parent but couldn’t build detached, their backyard was too small for the 4-foot side and rear setbacks Thousand Oaks requires for standalone units. We converted an existing 320-square-foot laundry wing into a Junior ADU, which California law permits with reduced setbacks because it stays within the existing footprint. The shared wall with the main house needed fire-rated drywall and a separate exterior door per R-2 occupancy code. We installed a 24-inch efficiency kitchen, a 3/4 bath with a 32-inch shower, and a mini-split system with independent thermostat. The parent moved in 7 months after we filed the permit. Written price: $89,000. Photo record shows every stage, including the fire-taping inspection that the city flagged and we corrected same-day.
Prefab ADU: Abodu One in North Ranch with HOA Coordination
North Ranch has an active HOA with design review that adds 45 to 60 days before city submission. We coordinated directly with the HOA architectural committee using Abodu’s finish samples and our rendered site plan, getting approval in 6 weeks. The Abodu One is a 500-square-foot unit we specified with James Hardie siding to match the main house, not the standard Abodu cladding. Crane access required a 40-foot boom reach over the pool equipment, which we priced in the written quote after surveying with the crane operator pre-contract. Installation day took 6 hours. Final with foundation, utility tie-ins, and deck: $195,000. The Haven Standard photo record includes the crane lift, the level check, and the final utility pressure test.
ADU Site Prep & Utilities: Wildwood Area with Severe Slope and Trenching
This Wildwood lot had a 22-foot elevation change from the street to the buildable area, with caliche rock at 18 inches that standard trenching equipment couldn’t break. We brought in a hydraulic hammer for two days, installed a 6-foot retaining wall with drainage weep holes, and trenched 85 feet for water, sewer, and electric in a single shared trench with 18-inch separation per Ventura County code. The drainage design had to handle the seasonal runoff that floods Wildwood Creek, so we specified a French drain system with a daylight outlet above the 100-year flood plain. Site prep and utilities alone: $67,000 written price. The photo record shows the rock layer, the hammer work, and the final compaction test. The detached ADU build is scheduled next; the same contract covers both phases at one price.
Interior Conversion: Lynn Ranch Basement to Code-Compliant Living Space
Lynn Ranch homes from the 1970s often have basements that were never permitted as living space. This one had 6-foot 10-inch ceilings, a single stair with no fire separation, and no egress window. We designed a legal secondary unit, not a full ADU, because Thousand Oaks does not permit basement ADUs with separate mailing addresses. The project added a legal bedroom and bathroom for the homeowner’s adult child, with an egress window well dug to 44 inches below grade and a fire-rated door at the stair. Ceiling height gained 4 inches by relocating ductwork to a soffit over the closet. The work required no zoning variance because we stayed within the existing envelope. Written price: $54,000. The photo record documents the egress window installation, the fire-taping, and the final inspection sign-off.
Want Results Like These?
Every project here started with a phone call and a free estimate. We’ll look at your lot, your existing structure, or your written estimate from another builder, and give you a real number you can plan around. Call (424) 395-4555 to schedule your free estimate. A live person answers, 24 hours a day.
Written by Nadia Ellery, Owner at Ellery ADU Studio Thousand Oaks, serving Thousand Oaks since 2015.