
ADUs & Additions in Mission Viejo
Detached ADUs, garage conversions, room additions and second storeys, designed, permitted and built. Designed, permitted and built by our own crews.
ADUs & Additions built for Mission Viejo properties
Association country. Nearly every tract carries a homeowners association with an architectural committee, and many rear yards are encumbered by slope maintenance easements that limit how far back a pool, deck or ADU can go. Pads are 1970s to 1990s cut-and-fill, so we verify fill depth before setting a shell elevation. Access is the other constraint: cul-de-sac lots with block wall returns often mean hand-dig or crane work rather than a wide gate.
Suburban tract pads, generally flat at the house with a graded slope at one or more property lines. Rear yards are moderate in size and almost always enclosed by block wall.
We are a design-build team, which means the people who draw your project are the people who build it. Design, engineering, permits and construction run through one project manager and our own crews, so nothing gets lost in a handoff between a salesperson and a subcontractor. We are licensed and insured, LIC #1119054.
Permits in Mission Viejo: Permits and inspections are handled by Building Services within the Community Development Department, reachable through the building services desk, with all permits and inspections now processed online through the city's Client Self Service portal for applications, plan submittal, fee payment and inspection scheduling. The Building Safety function is responsible for inspecting construction against approved plans and applicable ordinances. Nearly every residential tract is governed by a homeowners association with an architectural committee, and many rear yards carry recorded slope maintenance easements that restrict construction. Verify the association's design guidelines and any easement on the parcel before finalizing a backyard layout, since association approval runs on a separate track from city plan check.
What We Build
- HOA architectural committee submittals
- Slope easement and fill-depth verification
- Limited-access excavation planning
- Detached ADUs, ground-up
- Garage conversions to living space
- Junior ADUs within the main house
- Room additions and bump-outs
- Second-storey additions
- Full kitchens and bathrooms in the ADU
- Separate utility metering where required
- Private entries, patios and landscaping
- Plans, engineering and city submittals
- Title 24 energy compliance
Local Conditions
What building in Mission Viejo actually involves
Every city in Southern California builds differently. These are the things that change the scope, the schedule or the budget on Mission Viejo projects.
Pads built between the 1970s and 1990s are cut-and-fill, so fill depth needs to be confirmed from the geotechnical record before a shell elevation or footing depth is committed.
Recorded slope maintenance easements at the rear of many lots limit how far back a pool, deck or accessory structure can extend and who is responsible for the slope planting.
Cul-de-sac and pie-shaped lots with block wall returns often have no gate wide enough for equipment, so excavation becomes a hand-dig, conveyor or crane operation.
Expansive clay under much of the older tract housing drives deepened footings, reinforced flatwork and careful joint layout on large patio areas.
Investment
What this costs in Mission Viejo
Real Southern California ranges, not a teaser number. Every project is priced line by line after we have seen the site.
Detached ADU
$150,000 to $400,000+
What moves it: square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build
Garage conversion ADU
$80,000 to $180,000
What moves it: whether the existing slab and framing meet current code, how far utilities have to run, and the finish level of the kitchen and bathroom
Plans, drawings and permit management
$4,500 to $25,000+
What moves it: project type and size, whether structural engineering, Title 24 or a soils report is required, and how many jurisdictions or review bodies are involved
How We Build
Your Mission Viejo project, step by step
Feasibility
We check lot size, setbacks, utilities and access to confirm what your property will actually support.
Design & 3D
Layout, elevations and finishes, modelled in 3D so you approve the unit before submittal.
Plans & Permits
We prepare the full drawing set, handle engineering and Title 24, and manage the city submittal and corrections. In Mission Viejo that submittal goes to City of Mission Viejo Community Development Department, Building Services Division.
Foundation & Framing
Site prep, foundation, framing and dry-in by our own crews.
Systems & Finishes
Electrical, plumbing, HVAC, insulation, then kitchen, bath and interior finishes.
Final Inspection
We pass final inspection, walk the unit with you and hand over the keys.
Mission Viejo Questions
Common questions from Mission Viejo homeowners
Who issues the permits for this work in Mission Viejo?
City of Mission Viejo Community Development Department, Building Services Division. Permits and inspections are handled by Building Services within the Community Development Department, reachable through the building services desk, with all permits and inspections now processed online through the city's Client Self Service portal for applications, plan submittal, fee payment and inspection scheduling. The Building Safety function is responsible for inspecting construction against approved plans and applicable ordinances. Nearly every residential tract is governed by a homeowners association with an architectural committee, and many rear yards carry recorded slope maintenance easements that restrict construction. Verify the association's design guidelines and any easement on the parcel before finalizing a backyard layout, since association approval runs on a separate track from city plan check. We prepare the drawings, make the submittal and handle plan-check corrections ourselves, so you are not the one chasing the city.
What makes building in Mission Viejo different?
Suburban tract pads, generally flat at the house with a graded slope at one or more property lines. Rear yards are moderate in size and almost always enclosed by block wall. In practice that means pads built between the 1970s and 1990s are cut-and-fill, so fill depth needs to be confirmed from the geotechnical record before a shell elevation or footing depth is committed..
Which parts of Mission Viejo do you work in?
All of it, including Canyon Crest, Painted Trails, Casta del Sol, Deerfield. We are based in Los Angeles at Cahuenga Pass, so Mission Viejo is a short run for our crews rather than a job we service from out of the area.
What does adus & additions cost in Mission Viejo?
Detached ADU in this market generally runs $150,000 to $400,000+. What moves it is square footage, finish level, utility runs, and site access; garage conversions typically run well below a ground-up detached build. We give line-item pricing after seeing the site rather than quoting a number over the phone.
How long does an ADU take start to finish?
Plan a realistic year. Design and engineering typically take one to three months, city plan check and corrections add several more, and construction usually runs four to eight months depending on size and site access.
Is a garage conversion cheaper than a detached ADU?
Usually yes, and often substantially, because the foundation, walls and roof already exist. The trade-offs are that you lose the garage, and older slabs and framing sometimes need upgrading to meet current code.
Can I rent the ADU out?
California ADU law is designed to allow long-term rental, and an ADU is one of the few ways to add rentable square footage to a single-family lot. Short-term rental rules vary by city, so confirm your local ordinance before counting on that income.
Do you handle the permits?
Yes. Plans, engineering, Title 24 and the city submittal are all handled in-house, including responding to plan-check corrections. That is a service we sell on its own, so it is not something we hand off.
More services in Mission Viejo
Mission Viejo Guides
Planning guides for Mission Viejo homeowners
Costs, materials and process notes from our own projects.
ADU Cost Breakdown by Size in Los Angeles
A detached ADU in Los Angeles runs $150,000 to $400,000-plus. Here is the real cost broken down by unit size, with the soft costs, utility work and finish decisions that move the number.
Read guideGarage Conversion to ADU: The Step-by-Step Build
A garage conversion runs $80,000 to $180,000 in Southern California. Here is the real sequence, from slab testing and plan check to the raised floor, the mini-split and final sign-off.
Read guideADU Rental Income Maths in the San Fernando Valley
A one-bedroom ADU in the San Fernando Valley rents for roughly $2,100 to $2,900 a month. Here is the honest arithmetic on payback, carrying costs and what the unit adds to the property.
Read guideSecond Storey Addition vs Building Out: Which Costs Less
Building out runs $350 to $500 per square foot. Going up runs $450 to $700. Here is when the cheaper option is actually the wrong one, and what drives each number.
Read guidePlanning adus & additions in Mission Viejo?
Sit down with your project manager, go through the details, and get an accurate estimate for your property.
Licensed & Insured · LIC #1119054
