Three Timber-Lagging Walls Hardened Against Wildfire on Napa's State Route 128

State Route 128 has burned more than once. Along this scenic wine-country corridor, NanoTech worked with Valentine Corporation to coat three timber-lagging walls, 3,750 square feet in all, with Wildfire Shield.

In March 2025, three wood timber-lagging walls along Route 128 in Napa, California, were treated with NanoTech Materials' Wildfire Shield. Valentine Corporation did the work for the Department of Transportation. Together the walls add up to 3,750 square feet, and the aim was to make these roadside structures more durable as wildfire threats keep rising.

The crews held a high standard on the application, protecting the structures while keeping the natural charm of this well-known wine-country corridor.

Project at a glance

A wine-country highway with a long fire history

State Route 128 winds through Napa wine country, a corridor that has seen everything from small brush blazes to massive multi-hundred-thousand-acre complexes. The roadside timber-lagging walls that support the route are combustible and fully exposed, and any fix had to keep the area's natural and wine-country charm.

From brush fires to 360,000-acre firestorms

Route 128 has seen fires that range from fast-moving brush fires to multi-hundred-thousand-acre complexes, with evacuations, road closures and threats to wine country, according to CAL FIRE. That rising exposure is what pushed the effort to harden the corridor's roadside structures.

How the coating protects roadside structures

Timber ignites and chars under radiant heat and flame, then spreads fire and loses strength. Intumescent products only react once the wood starts to heat, so ignition can come before activation, and the char can smoke and off-gas.

A passive barrier that needs no activation energy

Wildfire Shield protects passively from the moment it cures, using patented ICP technology that pairs high emissivity, high reflectivity and low thermal conductivity into a high-temperature thermal barrier with no flame spread and no smoke (ASTM E84 Class A, 0/0). In testing witnessed by Department of Transportation personnel, coated timber lagging was held under a direct propane-torch flame for 20 minutes while the thermocouples behind the coating stayed near ambient.

Wildfire Shield applied across three walls

Working with Valentine Corporation, NanoTech-guided crews coated all three walls, sized at 550, 2,000 and 1,200 square feet. They cleaned and moisture-checked each substrate and built Wildfire Shield up in passes to the specified thickness. Careful workmanship kept the finish consistent while preserving the corridor's natural charm.

What the coating system delivered

•     3,750 sq ft of Class A coated timber lagging across three walls (ASTM E84, 0/0)

•     Passive, non-sacrificial protection with no activation energy

•     More durable roadside structures as wildfire threats rise

•     A finish that keeps the wine-country corridor's natural charm

•     A water-based coating with simple water cleanup

•     Backed by NanoTech's 10-year material warranty

Route 128 has faced everything from small brush blazes to 360,000-acre firestorms.

Route 128 has seen fires that range from fast-moving brush fires to multi-hundred-thousand-acre complexes, with evacuations, road closures and threats to wine country, according to CAL FIRE. 

A wine-country corridor, more resilient

Three walls and 3,750 square feet of roadside timber lagging now carry Class A passive fire protection, improving the corridor's durability while keeping its scenic character.

Finished in March 2025, Napa is among the most recent entries in NanoTech's growing Department of Transportation timber-lagging track record across California.

What this means for your team

The same outcome reads differently depending on your role. Here is what this project means for the people who own, specify and apply fire-protection coatings.

For DOT structural & fire-protection engineers

Wildfire Shield gives specifiers a documented, independently tested alternative to defaulting to concrete for fire-exposed wooden infrastructure. It is verified to ASTM E84 (Class A, 0/0), plus E119, E162 and E662, and it came through a 20-minute direct flame-impingement test on timber lagging witnessed by Department of Transportation personnel. That is the kind of evidence it takes to qualify a non-traditional material with confidence.

For DOT district managers & budget authorities

Coating in place, or shop-applying off-site, preserves existing timber lagging instead of replacing it with costlier concrete or steel. Wildfire Shield is non-sacrificial and is built to protect the structure across repeated fire events when the system is maintained, so it stretches mitigation budgets across more lane-miles while keeping crews and traffic moving.

For bridge & highway contractors / applicators

Wildfire Shield is sprayed or rolled with common equipment and conforms to the geometry of timber lagging, abutments and fences, with no jacketing or fabrication required. On-site or off-site shop application removes seasonal and just-in-time bottlenecks, and NanoTech's certified-applicator training and supervision keep DOT-specified work on schedule.

Wildfire Shield technical specifications

Wildfire Shield is a water-based, non-sacrificial fire-mitigation coating built on NanoTech's patented Insulative Ceramic Particle (ICP) technology. Key published properties are summarized below; confirm project specifics against the current Technical Data Sheet and SDS.

Frequently asked questions

How many Department of Transportation timber-lagging corridors has Wildfire Shield protected?

Wildfire Shield has been deployed across many corridors statewide, including Sequoia Highway 180, Salinas, Cook Valley on US 101, South Sequoia near Porterville, Santa Barbara Highway 192, Napa State Route 128, Felton Highway 9 and Ventura County Route 150 near Ojai.

How is Wildfire Shield different from intumescent fireproofing?

Intumescent coatings have to be triggered by fire. They char and swell only after the substrate begins to heat, so the wood can ignite before the coating activates, and the char can give off smoke and toxicity. Wildfire Shield is non-sacrificial and works the moment it is applied. Its mix of high emissivity, high reflectivity and low thermal conductivity reflects and re-radiates heat and slows the heat that reaches the wood, with no flame spread and no smoke development (ASTM E84 Class A, 0/0).

Can the coating survive more than one fire?

Yes. Because it is non-sacrificial, Wildfire Shield is designed to protect the underlying structure through repeated wildfire events when the coating system is inspected and maintained. NanoTech recommends yearly inspections for wear, cracking or damage, and worn areas can be touched up by overcoating rather than fully replaced.

How hot can Wildfire Shield withstand?

It withstands direct flame exposure up to 3,272°F (1,800°C). In testing witnessed by Department of Transportation personnel, coated timber lagging was held under a direct propane-torch flame for 20 minutes while the thermocouples behind the coating stayed near ambient.

Is it safe and environmentally responsible?

Wildfire Shield is water-based and non-toxic, with no reportable VOCs and no toxic runoff or leaching, and it is not classified as hazardous for supply or use. It cleans up with water and suits sensitive settings such as national parks and the wildland-urban interface.

Related resources

From NanoTech Materials

•     Wildfire Shield product page

•     Fire Protective Coating System overview

•     Wildfire mitigation applications

•     Industries we serve

•     Resource library and case studies

•     Request a quote or join the certified-applicator network

External references

•     CAL FIRE (California Department of Forestry and Fire Protection)

•     ASTM International fire-test standards

Talk to NanoTech about wildfire protection

Protecting timber lagging, bridges, utility poles, fences or homes in a wildfire-prone area? Talk to NanoTech about Wildfire Shield, or join our certified-applicator network. Call (888) 296-6266, email [email protected], or visit nanotechmaterials.com.

About NanoTech Materials. NanoTech Materials is a Houston-based materials-science company developing advanced coatings for energy efficiency and fire protection. Its Fire Protective Coating System, including Wildfire Shield, is built on patented Insulative Ceramic Particle (ICP) technology to protect critical wooden infrastructure and high-value assets from wildfire, buying time and saving lives.

_{© 2026 NanoTech Materials. All rights reserved. Performance data summarized from NanoTech technical documentation (TDS, SDS, Application & Technical Manual) and the Wildfire Shield Project Portfolio; confirm project-specific details and current published values with a NanoTech representative.}