







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Room Addition Contractor Across Westlake Village
A room addition in Westlake Village typically costs $210 – $390 per square foot for design, permits, materials, and licensed construction, with most additions landing between $85,000 and $280,000 depending on size, finish level, and how much custom millwork your HOA requires. That number holds when the price is fixed in writing before the first delivery, which is how Fielding ADU Thousand Oaks works. We serve Westlake Village daily, and our crews know the difference between a Thousand Oaks approval and a Westlake Village architectural review board standard. Call (805) 309-3020 for a written, line-item estimate on your addition.

Why Fielding ADU Thousand Oaks Is Westlake Village’s Preferred Room Addition Contractor Company

Fielding ADU Thousand Oaks is the ADU and room-addition specialist inside the Garrison Partners family, an independent local business held to The Garrison Standard since 2006. That standard has five parts, what we call The Garrison Code: show up in the window, price in writing, by the book, leave it clean, stand behind it for a year. For Westlake Village homeowners, the part that matters most is the written price. You approve a number on day one. That number is on the final invoice. No change orders, no surprise lumber surcharges, no “we hit a water line” add-ons.
Reed Calloway leads our room-addition work across Westlake Village. He and his team carry background checks and arrive in uniform, so you always know exactly who is on your property and why they are there. If something fails on your addition inside one full year, we come back and correct it at no charge under the 365-Day Done Right Promise. That guarantee is on paper, not just spoken.
The workmanship in Westlake Village is not like tract-home work. Homes off Lindero Canyon Road, along Westlake Boulevard, and inside the gated golf-course enclaves carry architectural expectations that a strip-mall renovation crew cannot meet. Our Room Addition Contractor team coordinates with local architects and designers weekly, and we stock the specific long-lead materials this market demands before the permit board even sits.
ADU Conversion in Westlake Village
An ADU Conversion in Westlake Village means converting attached or detached space, a garage, a bonus room, or an under-used wing, into a legal secondary dwelling with its own entrance, kitchen, bath, and address. In this city, the conversion almost always has to read as part of the original home, not as an attached apartment. That means the exterior finishes, stucco color, window style, and roofline need to match what the HOA already approved decades ago. Fielding ADU Thousand Oaks handles this daily.
Garage and Attached Conversions
Westlake Village garages attached to 1960s and 1970s semi-custom homes convert well because the eave lines and slab elevations usually align with the main house. We handle the structural upgrade, the new plumbing and electrical runs, and the fire separation wall the code requires, then we carry the stucco and tile-roof lines through so the conversion disappears into the original elevation.
Permit and HOA Coordination
The permit path in Westlake Village runs through the city and, in many associations, a design review committee. We pull permits by the book, submit the architectural drawings your HOA expects, and attend the review with you if needed. We can also work with the prefab platforms you may already be researching: Abodu, Cover, and Dvele all have product lines suited to constrained hillside lots in the Village, and we are fluent in their permitting and installation requirements.
Sunroom Builders in Westlake Village
Sunroom Builders in Westlake Village do not build a glass box bolted to the back of a Tuscan villa, not if the HOA has any say. A sunroom here is an attached garden room with architectural glass, custom arched millwork, and a thermal envelope that holds up to hot summer afternoons and cool, damp winter nights. It is the room that bridges the Mediterranean indoor-outdoor lifestyle this climate invites. Fielding ADU Thousand Oaks builds sunrooms that read as original to the house.
Arched Openings and Specialty Glass
The arched opening is the signature Westlake look. Custom arched millwork and true divided-light glazing cost more than stock rectangles, but they are the difference between approval and rejection. We order architectural glass, often low-E tempered units, and custom steel or clad-wood windows with lead times running 12 to 16 weeks. We lock the material price in writing before the order is placed, so you are not absorbing a supplier’s price increase mid-project.

Fire-Resistant Underlayment
Santa Ana winds move through the Conejo Valley and across the hills above Westlake Village every fall. Our sunroom builds include fire-resistant detailing behind the finish surfaces, James Hardie underlayment behind stucco, and non-combustible framing where the code now requires it. It is not the shiny part of the room, but it is the part that matters when the wind picks up.
Trusted Brands We Service in Westlake Village
We install and service room additions and ADUs built on the major prefab and modular platforms homeowners research first, including Abodu, Cover, and Dvele. We also build conventional additions using James Hardie siding and exterior products, which we use frequently on Westlake Village hillside lots for fire resistance and clean stucco lines. Tuff Shed-style structures cross our path less often on this tier, but when a homeowner wants a finished studio on a concrete pad, we can engineer it to the proper standard. Because we service these systems locally, we keep common replacement parts and trim stock close to Westlake Village rather than waiting on out-of-state dispatch.
Common Room Addition Contractor Problems We See in Westlake Village Homes
- HOA design rejection. A homeowner or a hurried contractor submits a design with horizontal siding, a flat roof, or black-framed windows, and the architectural review board bounces it. The project stalls for months. The fix is simple: mirror the existing smooth stucco, arched openings, and barrel-tile roofline from the first drawing, and you do not waste the review cycle.
- Long-lead glass and custom millwork delays. Arched windows, true divided lights, and specialty glass run 12 to 16 weeks from order to delivery. If those orders are not placed before foundation framing, the framing sits open through winter rain while everyone waits. We order these items first and fix their prices in writing at that moment.
- Labor assumed to be the schedule driver. On high-end work, labor does not set the calendar. Material fabrication does. A contractor who quotes a tight timeline without accounting for custom Tuscan window lead times is guessing, not scheduling. Our written price includes the material schedule, so you know when your windows arrive and when the roof goes on.
- Unfixed material prices. Lumber, steel, and glass prices move. If the contract does not fix them, you eat the difference. The Garrison Standard fixes every material price in writing before ordering, which means the addition you approve is the addition you pay for, no supplier surcharge line items.
Pricing for Room Addition Contractor in Westlake Village, CA
A conventional room addition in Westlake Village, built to HOA duplication standards with smooth stucco and a tile roof, runs $210 to $310 per square foot. Add custom arched millwork, specialty glass, and architectural designer coordination, and the range moves to $310 to $390 per square foot. A 400-square-foot master suite addition at the lower end lands near $85,000; the same square footage with custom steel windows, a matched barrel-tile roofline, and designer finishes pushes past $145,000. ADU conversions in Westlake Village garages typically run $150,000 to $240,000 before permit fees, depending on the structural work the existing slab and framing require. Sunrooms with arched openings run $90,000 to $180,000. These are real Westlake Village market figures, not state averages. We give every homeowner a free, written estimate with the exact number before any work starts. Call (805) 309-3020 to schedule yours.
We Also Serve Cities Near Westlake Village
Our room-addition and ADU crews serve Westlake Village and the surrounding communities, including Thousand Oaks, Agoura Hills, Oak Park, and Calabasas. If you are planning a garage conversion or addition anywhere around the Conejo Valley, you will get the same written price and the same one-year written guarantee we deliver to every Westlake Village homeowner we work with.
Serving Westlake Village, CA - Our Local Coverage Area
We’re based in the Westlake Village 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 Room Addition Contractor in Westlake Village
Your HOA’s architectural review board will require the addition to match the existing home’s stucco finish, window type, and roofline, which in Westlake Village usually means smooth stucco, arched openings, and barrel tile. If the design contrasts, it gets sent back. We submit designs that duplicate the existing exterior from the first drawing, which is the single biggest lever on your approval timeline. Call (805) 309-3020 and we can look at your specific covenants with you.
Custom arched windows, specialty glass, and custom millwork run 12 to 16 weeks from order to delivery, and they are the items that stall framing if they are not ordered early. On a Tuscan-style Westlake Village addition, those are usually the exact materials the HOA is requiring. We order them first and fix their prices in writing at order time, so the schedule holds and the cost does not drift. Call (805) 309-3020 for a written material schedule with your estimate.
Yes. We match existing barrel-tile rooflines and smooth stucco on Spanish and Tuscan-style homes throughout Westlake Village, including homes on hillsides and golf-course frontages. The matching work includes specified flashing and underlayment details so the new roofline does not just look right, it sheds water correctly where the old and new roofs meet. Call (805) 309-3020 and we will walk your roofline with you.
Santa Ana winds raise the fire-resistance requirements for exterior materials and venting on additions in Westlake Village. We build to those requirements with fire-resistant underlayment, non-combustible vent details, and James Hardie products where the code calls for them. On hillside lots, those details are typically enforced at inspection. Call (805) 309-3020 for a free estimate that includes current fire-code compliance for your lot.
You will need professional drawings, and on most hillside or custom-lot additions in Westlake Village, an architect or designer is the practical path to HOA approval. We coordinate with local architects and designers weekly and can bring one into your project, or work from your existing drawings. The written price can include that coordination so you know the full cost upfront. Call (805) 309-3020 to talk through your lot first.
Written by Reed Calloway, Owner at Fielding ADU Thousand Oaks, serving Westlake Village since the Garrison Standard began in 2006.









