Fast, Reliable ADU Builders Across Altadena
If you’re weighing an ADU on an Altadena lot, you’re likely already running into the part nobody warns you about: this is unincorporated LA County, not a city with a permit counter down the street. Every accessory dwelling unit permit in Altadena, even a small JADU carved out of an existing garage, routes through the LA County Department of Regional Planning and LA County Building & Safety. That means a different agency, a different set of plan-check reviewers, and a fee schedule that doesn’t match Pasadena’s. And layered on top of that, the January 2025 Eaton Fire created a County expedited fire-rebuild pathway that changes how an ADU can be sequenced here. We know that process cold because we’ve been through it on Altadena parcels since the fire. Call (254) 602-5618 and we’ll walk you through what your specific lot actually triggers before you spend a dollar on plans.
Why Lodgewick ADU Builders Is Altadena’s Preferred ADU Builders Company
Lodgewick ADU Builders is the ADU company of the Kingswell family, building in Altadena since 2010. Russ Delmar leads our Altadena work, and he’s the one who sits in on County plan-check calls when a reviewer raises a Chapter 7A question on an ember-resistant vent detail. That’s the difference between a permit that clears in weeks and one that bounces through resubmittals for months.
What homeowners in the foothills tell us they value most is the written price before anything starts. Not a range, not a verbal estimate, not a number that breathes once the concrete truck shows up. Every Lodgewick project operates under The Kingswell Guarantee: a written price, a defined arrival window, a clean job site, and a written guarantee on the work, with a free return visit if something fails within the 365-day window. That’s the 365-Day Done Right Promise, and it’s in writing on every Altadena project before the first footing is poured.
We also answer the phone. Live person, 24 hours a day, seven days a week. When you call (254) 602-5618 about a permit question or a change to your rebuild scope, you don’t get a voicemail loop. You get someone who can pull up your file.
ADU Design in Altadena
ADU Design on an Altadena acreage parcel isn’t a drafting exercise, it’s a site-planning exercise. Before we draw a single wall, we survey the lot, check the driveway grade for concrete-truck access, map where stormwater wants to go, and confirm the fire-hardening requirements the County plan-check reviewer will demand. On the foothill lots above the Rubio/New York Drive area, that often means the ADU gets placed where the grade works, not where the owner first pictured it. Detached ADU design in Altadena typically runs $8,500 – $18,000 for plans, engineering, and County-ready submittal documents, depending on slope, soils, and whether the parcel is in the Very High Fire Hazard Severity Zone.
Site plan and grading first
We start every Altadena design with a topo and a drainage call. A lot that looks flat from the street often drops two feet across the rear pad, and a swale or French drain has to be in the plan set before the County stamps it.
Chapter 7A built into the drawings
Altadena’s foothill exposure means the plans must show Class A roofing, ember-resistant vents, and non-combustible cladding within required setbacks. We draw those into the scope from day one, so the number you sign is the number that clears plan check.
Backyard ADU in Altadena
A Backyard ADU on an Altadena lot with acreage is a different animal than the flatland builds you see in Pasadena or San Marino. You’re typically dealing with long material hauls from the street to the rear pad, a pier-and-grade-beam foundation where the soil won’t carry a slab, and equipment access that sometimes stops at the curb. On a large, mostly cleared lot in the Altadena foothills above the Rubio/New York Drive area, we scoped a ground-up detached ADU with a Tuff Shed-style storage shop on the same pad. The driveway grade couldn’t carry a concrete truck to the far corner, so we staged materials at the street and ran a longer pump and conveyor haul. The ADU went on a pier-and-grade-beam foundation with a swale and French drain to move stormwater away from the pad. The County plan-check reviewer also required Chapter 7A ignition-resistant detailing, Class A roof and ember-resistant vents, that we had already built into the scope before quoting, so there was no resubmittal. Ground-up backyard ADUs in Altadena with these site conditions typically run $220,000 – $380,000, with the foundation, fire-hardening, and access line items driving the spread.
Access and equipment staging
If the concrete truck can’t reach the build site, the price changes. We scope the pump, the conveyor, and the material staging route before we quote, so the line item is there in writing, not a surprise later.
Foundations on Altadena slopes
Most Altadena foothill lots need pier-and-grade-beam rather than a simple slab. We price the geotech call, the piers, and the drainage swale as part of the bid. You’ll see exactly what that costs before you sign.
Trusted Brands We Service in Altadena
Our ADU Builders team works directly with established prefab and panelized manufacturers, including Abodu, Cover, and Mighty Buildings. On an Altadena rebuild lot where the primary residence is going up at the same time, a panelized ADU can cut months off the schedule because the wall, floor, and roof assemblies arrive ready to set. We match the manufacturer to your lot’s slope, fire zone, and access constraints. Abodu’s detached units, for example, go up fast on pier foundations and clear County plan check cleanly when the Chapter 7A details are documented correctly. We know which models work in Altadena’s Very High Fire Hazard Severity Zone, and which ones will trigger a resubmittal.
Common ADU Builders Problems We See in Altadena Homes
- Quoting a rear-pad ADU as if the street is the build site. On acreage lots, the rear pad can be 150 feet from the road. If there’s no equipment-access or long-haul line item in the bid, the concrete pump and material conveyor become change orders. We scope and price that access before quoting.
- Missing the Chapter 7A fire-hardening requirements. Altadena sits at the base of the San Gabriel Mountains, most of it in a Very High Fire Hazard Severity Zone. Class A roofing, ember-resistant vents, and non-combustible cladding within required setbacks aren’t optional, and the County will force them onto the plans. We put them in the bid up front.
- Assuming a Pasadena-style over-the-counter permit path. Every Altadena parcel goes to LA County Regional Planning and Building & Safety, not a city counter. Contractors who don’t catch that before project kickoff cause resubmittals and months of delay. We start every Altadena project by confirming the County route.
- Pricing a JADU conversion without an existing-garage assessment. Altadena’s older stock, 1920s and 1930s Craftsman garages especially, often has slabs and framing that won’t pass a County conversion inspection. We check the existing structure before pricing, so you don’t sign a number that collapses on demo day.
Pricing for ADU Builders in Altadena, CA
Here are real ranges for Altadena’s market, not national averages. A garage conversion to a JADU on a flat Altadena lot typically runs $95,000 – $165,000, assuming the existing slab and framing pass inspection. A ground-up studio ADU on a standard 7,500-square-foot lot runs $180,000 – $260,000. That same studio on a foothill acreage parcel with a pier-and-grade-beam foundation, a long material haul, and full Chapter 7A fire-hardening runs $240,000 – $360,000. The spread is access, slope, soils, and fire-zone materials, not markup. We’ll put your exact number in writing before work starts, and that number doesn’t move unless you change the scope. Call (254) 602-5618 to schedule your free estimate.
We Also Serve Cities Near Altadena
While this page is written for Altadena homeowners, our crews regularly cross into Pasadena, La Canada Flintridge, San Marino, and Sierra Madre for ADU builds and garage conversions. If your project sits on the edge of Altadena or in a neighboring city with its own permit path, we’ll tell you straight what changes. The site conditions and fire-zone rules vary block to block up the foothills, and we quote each one on its own terms.
Serving Altadena, CA - Our Local Coverage Area
We’re based in the Altadena 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 ADU Builders in Altadena
No, because Altadena is unincorporated Los Angeles County, not a city. There is no Altadena planning department or permit counter. Every ADU permit, including a JADU inside an existing garage, routes through LA County Department of Regional Planning and LA County Building & Safety. That’s a different agency with different plan-check reviewers and fees than Pasadena or Arcadia use. Call (254) 602-5618 and we’ll confirm the exact County path for your parcel before you pay for any plans.
Yes. If your primary residence was destroyed or damaged in the January 2025 Eaton Fire, your ADU may qualify to be permitted as part of the County’s expedited fire-rebuild pathway rather than as a standalone backyard unit. That can change sequencing, fees, and the plan-check queue. We’ve handled Altadena rebuild parcels since 2025 and know how to sequence the ADU so it doesn’t hold up the primary-residence permit. Call (254) 602-5618 with your parcel number and we’ll tell you what’s available.
Because the site itself adds cost: long material hauls where the concrete truck can’t reach the pad, pier-and-grade-beam foundations on sloping ground, stormwater swales and French drains the County requires, and Chapter 7A fire-hardening materials. On a flat Pasadena lot, the crew unloads at the curb and pours a slab. On an Altadena foothill lot above New York Drive, we’re staging at the street and pumping materials back. Those are real line items, and we put them in writing before you sign.
If your parcel is in the Very High Fire Hazard Severity Zone, which covers most of Altadena’s foothill exposure at the base of the San Gabriels, the County will require Class A roofing assemblies, ember-resistant vents per CA Building Code Chapter 7A, and non-combustible exterior cladding within required setbacks. These aren’t optional upgrades. We price them into the bid from day one so your number clears plan check the first time. Call (254) 602-5618 for a free estimate that includes your specific fire-zone requirements.
Often yes, and on Altadena’s older lots it’s frequently the most cost-effective path. Many 1920s through 1960s Craftsman and ranch homes here have detached garages that are prime JADU or ADU conversion candidates, provided the existing slab and framing pass a County inspection. We assess the structure before pricing, so you know whether you’re looking at a true conversion or a rebuild. Assuming the structure passes, a garage conversion in Altadena typically runs $95,000 – $165,000. Call (254) 602-5618 and we’ll take a look.
Get Your Altadena ADU Estimate in Writing
If you’re planning an ADU, JADU, or garage conversion on an Altadena parcel, start with a written price, not a guess. We’ll walk your lot, check the access, confirm the County permit path, price the fire-hardening, and put the whole number in writing before any work starts. That’s The Kingswell Guarantee, and it’s been our standard on every Altadena project since 2010. Call (254) 602-5618 today to schedule your free estimate.
Written by Russ Delmar, Owner at Lodgewick ADU Builders, serving Altadena since 2010.