Fire-resistant NUDURA ICF custom homes for wooded foothill lots around Grass Valley, Nevada City and Penn Valley.
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Western Nevada County, around Grass Valley, Nevada City, Penn Valley and Lake Wildwood, is forested foothill country where many homes sit on large wooded lots. It is beautiful and it is fire country: much of the area is mapped as a high or very high fire hazard severity zone, and homeowners here know how hard it can be to find and keep insurance.
Building with NUDURA insulated concrete forms gives you noncombustible, steel-reinforced concrete walls with a fire-resistance rating of up to 4 hours. Combined with a Class A roof, ember-resistant vents, enclosed eaves and defensible space, an ICF home is designed to resist the embers and radiant heat that destroy most homes in wildfires. It also stays comfortable through foothill summers and snowy winter days with lower heating and cooling bills.
Nevada County also includes Truckee and Soda Springs in the high Sierra, where we have built several ICF homes. See our Truckee–Lake Tahoe page for mountain builds.
Real projects from our portfolio, with photos and the full story of each build.
NUDURA ICF Home Construction in San Miguel, CA — The Humphrey HouseView project →
Insulated Concrete Form (ICF) Home Construction in Soda Springs, CAView project →
High‑Elevation Mountain Home Built with Nudura ICF Technology in Soda Springs, CA | Part 2View project →
Finished Mountain Modern ICF Home in Soda Springs, CA: A Turnkey BuildView project →
Villa Boucetta Foundation Pour: Building the Base of a Luxury ICF Home in Indio, CAView project →
Custom ICF Home Construction in Santa Rosa, CA – Second Floor ICF Walls & Concrete PourView project →ICF handles those risks in the walls themselves — and it's built to the same codes your county already enforces.
NUDURA ICF walls carry a fire-resistance rating of up to 4 hours. Finished in stucco or fiber cement, they give you a noncombustible wall designed to meet California's Chapter 7A wildfire (WUI) building standards. We pair them with a Class A roof, ember-resistant vents and enclosed eaves.
Many Californians in fire-prone areas have been non-renewed or pushed onto the FAIR Plan. The state's Safer from Wildfires framework rewards home hardening — a Class A roof, ember-resistant vents, enclosed eaves, a noncombustible base of the walls and a 5-foot ember-resistant zone. In an ICF home we build every one of these in from day one, so it's documented when you shop for coverage.
PG&E's average residential rate reached about 34¢/kWh in 2026, up 56% since 2021 (CPUC Public Advocates Office). ICF walls are continuously insulated and airtight, so heat pumps run less. In third-party testing, NUDURA walls cut energy use by up to 58% compared with conventional construction.
Concrete mass and continuous foam keep indoor temperatures steady through 100°F Valley afternoons — when time-of-use electricity costs the most. A tight envelope with filtered ventilation also helps keep wildfire smoke outside.
Every ICF wall is a steel-reinforced concrete wall, engineered by a licensed structural engineer to the California Building Code for your site's seismic, wind and snow loads.
California's 2025 Title 24 energy code (in effect since January 1, 2026) raised the bar for walls and windows. New Zone 0 ember-resistant rules for high-fire-hazard areas are being finalized. We design to current Title 24 and Chapter 7A, and track the Zone 0 rules as they're finalized, so plan check goes smoothly.
Performance figures published by NUDURA for its ICF wall system, compared with typical wood framing.
Sources: NUDURA residential brochure and ICF performance data (energy savings from third-party testing by CLEB Laboratories / ICFMA; ASTM C1363 R-value testing), UL fire-resistance listing U930 (4-hour rating with a 6-inch or larger core). *Wood-frame fire and wind figures are from NUDURA’s ICF vs. wood-frame comparison; the source does not specify the wood wall assembly, and actual ratings vary by assembly. Results depend on design, climate, finishes and installation. STC 50 assumes a 6-inch or larger core with code-compliant finishes on both sides.
From the Sierra snowline to Wine Country and the desert — every wall below was stacked, reinforced and poured by our own team.
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Have a lot, a set of plans, or just an idea?We'll review it with you and map out what an ICF home would take — free.
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NUDURA forms are interlocking panels of EPS foam that we stack, reinforce with steel and fill with concrete. The result is one solid wall that is structure, insulation and air barrier all at once. We manage every step around it.
NUDURA certified team20+ NUDURA ICF homes built across California
NUDURA ICF · Built by Tenax
Most builders hand you a price per square foot. We walk through your lot, your plans and your budget, so you see the real picture first.
You'll always know what's next, who's responsible and what it costs.
Tell us about your lot, the home you have in mind, your budget and timing. We'll confirm ICF is the right fit before anyone visits.
We review your lot and plans — or start the design with you — and prepare a preliminary budget and timeline for your ICF home.
The day you sign, we open a group chat with your whole project team. Engineering, permits, foundation, ICF walls and finishes follow, with weekly updates until you get the keys.
One dedicated team from first call to move-in — plus a shared group chat from day one.
“I've had the opportunity to work with Tenax Construction on multiple projects as the engineer of record… Their approach to design and construction is practical and focused on efficient execution in the field, with a consistent standard of quality across conventional residential and high performance, high end construction.”
“We had an overall great experience… for our total whole house renovations and ADU detached garage conversion. We went with [them] against other companies for their in house team on all aspects of the process (design, electrical, plumbing, planning, and supplies)… [He] handles all interactions with the city on permits and inspections.”
“[They] delivered an outstanding full house remodeling experience. Their professionalism, expertise, and commitment to excellence were evident at every stage of the project… Their communication was top-notch, and they managed the project within the agreed-upon budget and timeline.”
A higher upfront investment, with potential long-term savings. Here's how it usually adds up in California.
On the total cost of the home. Your exact number depends on design, wall height and site.
In NUDURA's third-party testing — more valuable as California electricity rates keep rising.
Concrete walls don't rot, warp or feed termites — and it stands up to fire, wind and earthquakes.
Cost premium per Tenax project experience; energy figure per NUDURA published third-party testing. Insurance availability and premiums are set by insurers — we can't guarantee coverage or discounts.
Insurers set their own rules, so no builder can guarantee coverage. What we can do is build a home with the features California’s Safer from Wildfires framework recognizes, on top of noncombustible ICF walls, and document them so you can show your insurer exactly how the home is built.
The Nevada County Building Department for unincorporated areas; the cities of Grass Valley and Nevada City for homes inside their limits. We handle the submittal.
Yes. Truckee and Soda Springs are in Nevada County too, and we have built several ICF homes in the Soda Springs area. See our Truckee–Lake Tahoe page.
Typically about 5–10% more for the total home. You get a preliminary budget at the free consultation and a detailed estimate once the design is set.
Tell us a little about your project. We'll take it from there.
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