Berkeley Tuolumne Camp

Berkeley Tuolumne Camp is a beloved family camp operated by the City of Berkeley, providing social, nature-based and athletic programs for all ages, including hiking, nature studies, water sports and more. It is located on a 30-acre site along the South Fork of the Tuolumne River in the Stanislaus National Forest, just west of Yosemite National Park.

Rebuilding for resilience

The camp, established in 1922, has a deep history in the region, having served children and families for 91 years as a recreational retreat before it was destroyed by the Rim Fire in 2013.

Of the original 138 buildings within the camp, 120 were unsalvageable, completely levelled by the intense flames and ember exposure. Architect and Design firm Seigel and Strain were tasked with the extensive design and rebuild of Berkeley Tuolumne Camp with more sustainable and fire safe building materials. In total, the team would construct approximately 100 new structures totalling 40,000 sq. ft. This included a new dining hall, recreation hall, amphitheater, nature center, sauna, camp office and store, camper and staff cabins, restrooms and other infrastructure. Facilities were strategically located to comply with state, local, and federal code and to minimize disruption to sensitive site habitats. All amenities are knit together by a path system that maximizes the camper experience of the densely forested and mountainous Sierra landscape.

Rebuilding for resilience

The goal: Fire resistant roof system designed for high-risk WUI zone

The design of the rebuilt camp focuses on safety, resilience, and durability to ensure that it can stand up to higher fire risk and more extreme weather events brought about by a changing climate. The potential for wildfires in the heavily forested Tuolumne region remains a serious, ever-present reality. Mitigating risks was the primary goal of the Berkeley Tuolumne Camp rebuild, along with addressing common challenges in seasonal buildings such as maintaining more stable indoor temperatures, reducing the potential for moisture issues, and improving indoor air quality. Respecting the natural environment around which the camp and its programming is centered, the project team also sought to incorporate sustainable building materials, where possible.   

The Challenge

Building among the mixed conifer forests and chaparral/oak woodlands makes fire resilience of utmost importance. Yet, a County of Tuolumne Grand Jury report following the Rim Fire noted that, “due to growth and low-density development within Tuolumne County and the lack of regular burning to reduce fuel buildup, the local landscape remains susceptible to destructive fires in future.” Climate change is intensifying this risk, with the report also stating that “of the 20 most destructive fires in California’s history, 10 have happened within the last four years and, according to Stanford University School of Earth, Energy, and Environmental Sciences, in the last 50 years, summer temperatures have increased by 2.5 degrees and extended periods of drought have become normal.” As weather patterns continue to change, the need to protect buildings and the people they house has become essential, and local officials are tightening fire codes in Wildland-Urban Interface (WUI) zones across North America to ensure safety is prioritized. Tuolumne County is classified as Very High Fire Severity Hazard Zone (VHFSHZ). During the Rim Fire, it was determined that, predominantly, embers driven by winds created by the intense heat of the wildfire were the ignition source with fire originating on the roofs of most of the structures at Berkeley Tuolumne Camp. As a result, Seigel and Strain Architects sought to create a more fire-resistant roof system design that meets the requirements for Class A—the highest rating, offering the highest resistance to fire when tested in accordance with ASTM E108 (UL 790). 

Building among the mixed conifer forests and chaparral/oak woodlands makes fire resilience of utmost importance.

The Solution

Several factors made ROCKWOOL Toprock® DD and ROCKWOOL Multifix™ stone wool insulation products the leading choice to help meet current fire code with Class A fire-rated roof assemblies. First and foremost, the ROCKWOOL stone wool roof board products are classified as non-combustible when tested in accordance with FM 4470 and both have demonstrated acceptable performance in a variety of fire tests, including Standard Test Methods for Fire Tests of Roof Coverings – Class A (UL 790 / ASTM E108) and Fire Tests of Building Construction and Materials (UL 263 / ASTM E119). Additionally, ROCKWOOL stone wool insulation products, Toprock® DD and Multifix™, are listed in the California Office of the State Fire Marshal’s (SFM) Building Materials Listing Program (BML), having been tested for required product performance and reliability features by an SFM-accredited laboratory. This provided the specifying architects and owners with confidence that stone wool roof boards would meet the high standard of fire resistance required in Tuolumne County, given the region’s designation as a Very High Fire Severity Hazard Zone. Understanding that the camp would house children, who are a vulnerable population in fire events, it was also deemed beneficial that ROCKWOOL stone wool insulation products offered the lowest possible index for flame spread and smoke development—zero in both instances when tested in accordance with ASTM E84 (UL 723). That means the insulation will not contribute to the spread of fire or to toxic smoke or harmful gases in the event of a fire. ROCKWOOL stone wool also offered the highest resistance to fire—up to a temperature of 2,150°C—a performance characteristic that makes it ideal in applications that must meet WUI zone fire code requirements. Made primarily of stone, the ROCKWOOL stone wool insulation roof products ultimately contributed to Berkeley Tuolumne Camp’s enhanced life and fire safety measures. Other enhancements to the rebuilt camp include hydrants and hookup points now giving firefighters access to 240,000 gallons of water stored in a massive tank on a nearby hillside, while the new dining hall has a sprinkler system that covers everything from the kitchen to the underside of its deck. New structures also now comply with updated building codes requiring them to use fire-resistant materials. City officials noted the “goal is to give the camp a better chance of survival when—not if—it’s threatened by a wildfire again.”

ROCKWOOL Toprock® DD and ROCKWOOL Multifix™ stone wool insulation products


Roof Assembly – Top Down:

  1. Corrugated Metal Roofing
  2. Drain Mat
  3. Vapor permeable underlay
  4. Coverboard/insulation (ROCKWOOL Multifix™)

4b. Additional Insulation for R 20 assemblies (ROCKWOOL Toprock® DD)

4c. Z-girts between insulation layers

  1. Ice and Water shield
  2. Plywood deck

ROCKWOOL Toprock® DD and Multifix® stone wool insulation contributed to a wide variety of other project goals, as well. In addition to improving the fire resilience of the camp structures, the design team sought to create more stable indoor temperatures in the unconditioned three-season buildings, especially considering the wide variation in the local climate. Temperatures range from an average low of 30°F in January to an average around 90°F in July. Insulating with stone wool will contribute to greater indoor comfort in all seasons, including the very hot Tuolumne County summers. The region also experiences 62.5 inches of snow each winter—more than double the national average. As such, the high point load resistance of stone wool roof boards was an extra benefit appreciated by the design team. Being unconditioned, long-term durability of the camp buildings was a further consideration. The stone wool products’ resistance to moisture, mold, and rot was identified an important benefit, as was the vapor permeability which would allow any condensation or moisture to dry out should it enter the assembly. Thus, Toprock® DD and Multifix™ will help mitigate possible risks while contributing to better indoor air quality and potentially reducing repair and maintenance expenses in future. Ease of install was a coveted feature of both stone wool products. The Multifix™ dual-density roofing insulation boards additionally offered excellent compatibility with the Vaproshield SlopeShield® Plus SA underlayment.  This helped achieve reliable adhesion thanks to the mineral-coated fibreglass facer, contributing to an air tight roofing assembly and improved durability amid the region’s climate extremes. Having taken nearly 10 years to raise funds and rebuild following the Rim Fire, it was vitally important that the camp be constructed to better withstand the test of time and conditions, and stone wool insulation will play a key role to that end.

roof assembly details

Another factor that contributed to the specification of ROCKWOOL stone wool roof insulation was its sustainability profile. Surrounded by and teaching a deep respect for the natural environment, Berkeley Tuolumne Camp and its rebuild team aimed to incorporate as many natural and/or sustainable building materials into the camp buildings. Made primarily of stone, a natural and abundant raw material, ROCKWOOL insulation was deemed a very good fit from that perspective, further supported by environmentally-conscious manufacturing processes and a clear commitment to product transparency. With many of the products’ properties and performance characteristics being instilled by nature, including their superior fire resilience and durability, ROCKWOOL stone wool roof products were favoured.

Circularity exists inherently in nature, with renewal reinvigorating the landscape. This is now mirrored in the resurrected camp, with it now built better and more robust in time for its centennial anniversary. Every effort has been made to ensure it will remain in place for children and families to enjoy for generations to come.

Groveland, CA

Berkeley Tuolumne Camp

Groveland, CA

Project Data


Construction Commenced: May 2020

Completion: 2022


31858 Hardin Flat Road

Groveland, CA   95321

WUI Zone - Stanislaus National Forest (Yosemite area)

Climate Zone

Mixed-Dry – Climate Zone 4B

Fire Hazard Severity Zone

Very High Fire Severity Hazard Zone (VHFSHZ)

Performance Targets

Fire resiliency

Moisture Control




Seigel & Strain Architects

General Contractor

Kitchell Corporation

Roof Contractor

Boyer Construction

Building Type 


Dining Hall; Rec Hall; Managers Cabins; small cabins


100 buildings totalling 40,000 sq. ft.

Project Value

 $54.7 million


Toprock® DD