On the Radar

Spray foam Magazine – Winter 2021 – Occasionally, jobs come along that are extra special and the following was one of those. Owner of Allstate Spray Foam Insulation, Rusty Schrader was intrigued when he got a call from Jesse Campa, a project manager at Nations Roof about subcontracting for them on an historical radar tower.

Mount Umunhum is one of the highest peaks in the Santa Cruz Mountain Range at 3,486 feet and it’s where the Umunhum radar tower stands. Known locally as the The Cube or The Box, the 85-foot-tall, 60-year-old landmark tower is where Air Force technicians perused the skies for Russian bombers during the Cold War. The Air Force base closed in 1980 and the Open Space District purchased the summit in 1986. It was padlocked for decades, while it lobbied the Pentagon and Congress to pay for cleanup and renovations, which never happened. Then in 2013, former U.S. Rep. Mike Honda secured millions of dollars in federal funding.

The district demolished many of the buildings, but they left the distinctive concrete radar tower building. The radar tower was nearly demolished with several other buildings in the vicinity, but veterans and historic preservation supporters fought to keep it, and the tower is now on a list of important historic sites. 

This tower is currently being restored and spray foam is helping in these preservation efforts.

From 1957 to 1980, the Almaden Air Force Station operated on its summit, scanning for Soviet attacks that never materialized. Air Force personnel and their families even lived at the remote station, which included homes, a gymnasium, garages and even a bowling alley. Construction crews were called in to repair the cracks and voids in the concrete, remove asbestos, install new doors, rebuild the structure’s drainage system, coat the exterior walls with a layer of new concrete and treat with a waterproof sealant. It was then time to fix the roof.

A giant antenna was once on top of the radar tower, painted in an orange and white checkerboard pattern, which rotated every 12 seconds. It was taken down as soon as the Air Force left in 1980, and the process of its removal, as well as the building’s age left the roof full of cracks and open ducts that needed to be sealed up due to wildlife entering the structure through them.

Allstate Spray Foam Insulation had four crew members on the radar roofing job along with Jeremiah Schoneberg, a technical support manager at SWD Urethane, who was there to check the foam density and job progression. The roof took two days to spray but the crew were not asked to spray the inside of the tower, Schrader explained, “No one is ever allowed to enter the tower again. The goal was to restore the building, so it stops deteriorating and collapsing. 

You can literally drive right up to the building and people go hiking all the way around it, so they needed to make it structurally sound for safety reasons and to preserve it. This job was not for an insulation factor; we just filled the void with foam so there was no air movement.”

On the first day of spraying, the Allstate crew headed up the summit with their gear. The tower had scaffolding all the way up with a walkway around the building at the top. The crew also took their reliable hydraulic proportioner, the GUSMER GH-2, with the boss double gun set up. The crew used an electric lift to get the hoses up to the roof with their rig down below.

After the Allstate crew cleaned the substrate, they sprayed SWD QUIK-SHIELD 144 closed-cell spray foam. This foam also has the bonus of having a low global warming Potential (GWP), blowing agent, and is free of Hydrofluorocarbons (HFCs). 

Its high-performance insulation and air barrier are perfect for both residential and commercial construction, increasing jobsite efficiency and overhead costs. Once the spray foam was applied, Nations Roof came in to sheet it with a vapor barrier and a Thermoplastic polyolefin (TPO) roof on top of that.

The summit is open to the public once again, with hikers and history buffs all enjoying the views near the restored tower overlooking downtown San Fran, Mt Tamalpais, Monterey Bay, Mt Hamilton and beyond. Joining its efforts with a roofing company and construction workers, Allstate Spray Foam Insulation has played their part in restoring this historic landmark, and in turn will always be a part of its history.