Mission Possible: Tame Termites

Over more than two centuries, it has been subjected to earthquakes, floods and long stretches of neglect. And now, the historic mission at San Juan Capistrano is under siege by an army of hungry foes: termites.

Termites had previously invaded the mission, leaving telltale holes in doorjambs, headers and beams. But the problem became so acute this year, mission officials said, that a massive extermination was required.

“We wanted to reinforce wood beams and other wood structures in the Serra Chapel when we realized the damage was considerable,” said Mechelle Lawrence, the mission’s executive director.

On Tuesday, workers began fumigating the chapel and four other buildings after covering them with tarps to contain the poisonous gas.

The work is expected to take all week. The chapel and other buildings will be closed until Friday. The mission’s Soldier’s Barracks, Great Stone Church and outdoor areas, which are not being fumigated, are open.

In the mission’s chapel and especially in the South Wing -- both among the 229-year-old structures -- termites have eaten through a few of the wooden beams that help support the structure.

The decay is not something the mission can take lightly. Architectural review and approval are needed before carpenters can buy replacement lumber, Lawrence said.

After the termites are eradicated, preservationists will assess the damage. In some cases, if a wooden beam bears no weight and is 50% damaged, they may hide the damage with epoxy filler. If the beam supports weight, however, it mostly likely will be replaced, she said.

“We try to use the least invasive approach,” she said.

Old adobe bricks and wood and clay roof tiles from the time of the American Revolution are irreplaceable. In addition, to seek grants for preservation projects, the mission must adhere to federal preservation guidelines, said Sam U’Ren, mission conservator.

The mission’s preservation team, with the help of a consultant, identified two types of invaders: dry-wood termites and larger termite colonies that live in the ground.

In California, colonies of subterranean termites have 50,000 to 100,000 termites, said Bill Quarles, a spokesman for the Bio-Integral Resource Center, a Northern California organization seeking alternatives to pesticide treatment.

Fumigating underground termites is futile. They are best attacked with bait containers dug into the ground, he said. The mission will use fumigant on the dry-wood termites and bait containers on the subterranean variety, officials said.

Dry-wood termites have nests containing about 2,000 insects. Like their subterranean cousins, they fly to establish new colonies and eat their way into a crack in the wood or drill their way in, Quarles said.

“Given the age of the mission, you can do some damage to the structure with alternate methods [of termite control], like drilling to inject a chemical or using microwaves, which can char wood,” he said.

The eradication project had been estimated to cost $40,000. But Western Exterminator Co., Dow AgroSciences and Doctor Fume Inc., have donated portions of their work, cutting the cost in half, Lawrence said.

Working on the historic structure has taken months in preparation, said Chuck Moore, a Western Exterminator service manager. He said the building couldn’t be treated as “just another commercial building.” It had challenges that included removing fragile clay-barrel roof tiles to clear a path for workers to walk on.

“You’ve got fragile bricks that can crack easily and other things like that roof spout up there,” Moore said, pointing to a series of 10-inch clay rain spouts jutting from a wall. “We have to be very careful with the tarp overhang because it can break that off.”

On Tuesday, the mission had signs apologizing to visitors that some buildings had to be closed.

“You know, it’s disappointing,” said Judy Caratola, who was vacationing with her family from New Jersey. “But we understand that they need to do it. After all, it does have to be preserved because it’s so old.”