James Hardie ADU Builders Nationwide

James Hardie ADU Builders in San Francisco: What to Know First

James Hardie ADU builders in San Francisco typically charge between $280 and $420 per square foot for a complete accessory dwelling unit, which means a 500-square-foot backyard unit lands somewhere around $140,000 to $210,000 all-in, including Hardie siding, permits, and finishes. As an independent James Hardie service provider, Lodgewick ADU San Francisco handles everything from the concrete pour to the final siding inspection, with a written price before any work starts and a 365-Day Done Right Promise in your hand before the first nail goes in.

Call (707) 760-0502

This page is for homeowners in San Francisco who already own a property with James Hardie siding, or who are planning an ADU that needs to match existing Hardie lines like HardiePlank lap siding or the TruExterior trim system. If you’re trying to figure out whether your garage conversion can keep its current Hardie cladding, whether you need a full re-side, or what a junior accessory dwelling unit might cost on your specific San Francisco lot, you’re in the right place. Call (707) 760-0502 and Russ Delmar will pick up.

How James Hardie Products Fail – and How We Fix Them

James Hardie fiber cement is a solid product, but it’s not invincible, and San Francisco’s marine climate exposes every mistake. Here’s what we see on ADU projects across the city:

• HardiePlank lap siding wicking at the cut edge. On San Francisco ADUs within two miles of the ocean, like the Sunset or the Richmond, we routinely see unpainted field cuts on HardiePlank that absorb fog moisture and swell at the bottom edge. The telltale is a chalky white line two to three inches up from the drip edge. Our fix: we cut with a shearing tool or diamond blade, prime every field cut with Hardie’s approved edge sealer, and flash the sill. Skipping that primer step is how a 30-year siding product fails in eight.
• HardiePanel vertical siding installed without the drainage gap. Some San Francisco ADU additions from the early 2010s used HardiePanel directly over building wrap with no rainscreen. Behind stucco or wood, that traps moisture and you get soft sheathing behind a panel that still looks fine from the street. We see this in garage conversions around Bernal Heights where the existing wall was left in place and the builder just furred out over it. Our fix: we open the wall enough to check sheathing, add a rainscreen gap per Hardie’s installation specs, and replace the wrap before re-installing.
• Trim board joints on HardieTrim batten boards failing at caulk lines. HardieTrim holds paint well, but the seam where a batten meets a window casing fails when the installer used a cheap acrylic caulk. The joint opens, water follows the fastener line, and you get streaks of rust down the board. We saw this on a Dogpatch ADU where rust stains looked like a leak from the window, but it was actually caulk shrinkage at the batten. Our fix: we pull the old caulk, re-seal with a high-quality elastomeric, and touch up with a paint match that includes the correct sheen.
• HardieSoffit panels sagging on the underside of an ADU eave. HardieSoffit installations from the mid-2010s sometimes used mismatched fastener schedules and the panels start to bow along the reveal line. It’s a cosmetic issue that becomes a water issue if the bow opens a gap at the rake. We fix the fastening pattern, re-align, and replace any cracked sections, which is easier on a detached ADU than trying to match a full re-side.
• Brittle corners on older HardiePlank from the mid-2000s. Before James Hardie reformulated certain regional lines, some San Francisco homes had HardiePlank that became chalky and brittle at outside-corner miters within fifteen years, not thirty. If your ADU shares a wall with a main house from that era, the corner returns may be the first thing to snap. Our team replaces the corner with a metal outside corner profile whenever possible because it sheds water better than a raw miter in this climate.

Our James Hardie ADU Builders Process

Here’s how a James Hardie ADU build or siding repair works with Lodgewick ADU San Francisco, from first call to final walkthrough:

1. 1
   Site walk. Russ Delmar walks the property before quoting a number. He’s done ADU projects within a few blocks of Dolores Park where Victorian lot lines make every build its own puzzle, and he wants to see what the Hardie siding looks like, what’s behind it, and how the drainage flows.
2. 2
   Written price. You get a line-item price in writing before any work starts. No change orders at the door. The price includes materials, labor, permit fees, and disposal.
3. 3
   Parts decision. For a James Hardie job, we use OEM Hardie products for the siding face, but we’ll recommend paint-match and trim systems that hold up better in San Francisco’s fog belt than the original spec when that’s the right call.
4. 4
   Permits and prep. We pull permits for ADUs in San Francisco, handle the inspections, and protect the existing siding on any shared wall. The job site stays clean.
5. 5
   The build. Our crews install per James Hardie’s written installation specs, including the edge sealing and flashing details that most failures trace back to. We’re background-checked and uniformed, and you’ll always know who’s on site.
6. 6
   Inspection and the 365-Day Done Right Promise. After final inspection, you get the guarantee in writing. If anything fails within 365 days, we come back and make it right.

Why San Francisco Homeowners Call Lodgewick ADU San Francisco for James Hardie Work

Most homeowners who call us have been burned before. They had a price change at the door. A crew that stopped showing up. A repair that failed a month later. That’s why we run every project through The Kingswell Way: say the price before the work, show up in the window we gave you, leave the site cleaner than we found it, put the guarantee in writing, and come back if the work fails within 365 days.

We work hands-on with James Hardie, and we also know how Abodu, Cover, and Dvele prefab ADU systems integrate with an existing Hardie-clad house in San Francisco. If you need a custom build, a prefab installation, or a garage conversion, we’ll match the materials to your lot, budget, and timeline, not the other way around. A live person answers our phone 24 hours a day, seven days a week. No voicemail loops.

I’m Russ Delmar, and I grew up in the San Gabriel Valley, where my dad kept framing squares on the kitchen table like most people keep mail. I studied construction technology at Los Angeles Trade-Technical College and spent years doing everything from foundation work to finish carpentry before ADU work, which is accessory dwelling units, meaning a second living space built on a property you already own, became the focus I’d been looking for. Tell me what the space needs to do, and we’ll figure out how to build it right.