Whitewash the Petaluma Adobe? To those accustomed to the trademark adobe brick walls of the historic building, it might sound like sacrilege. But according to local advocates for the building, plastering and whitewashing is not only a means to preserve the structure, it's a way to restore its original appearance.

The move comes as the group that rescued the park from imminent closure — the Sonoma/Petaluma State Historic Parks Association — seeks to address a huge backlog of maintenance needs.

Last year, the association raised $70,000 and entered into a donor agreement with the state to keep the Adobe open when the state parks department announced that, due to a lack of funds, it would have to close 70 parks, including the Petaluma Adobe. Not long after the association raised the funds needed to keep the Adobe open one more year, it was discovered that top parks officials had kept tens of millions of dollars hidden away for more than a decade — even as the parks faced closure.

Upon discovery of that cache of money, buried in two special funds, the parks department agreed to match the money raised by local parks advocates to keep parks open.

In the case of Petaluma Adobe, it means the park is guaranteed to stay open through June of 2014. There are no guarantees after that, but local parks supporters are hopeful that the state's worst budget problems are behind it and that parks will be recognized as a priority in the future.

The association has existed since the '80s to fundraise for the Adobe and the Sonoma State Historic Park and help expand interpretation and education at the two parks. Now that keeping the Adobe open is not its main fundraising priority, the association has turned its attention to other projects — like a maintenance backlog, built up over years of scarce state funding.

"As one of the oldest buildings in the area, there's a lot of deferred maintenance," said Philip Sales, president of the association. "It's really an issue that's come to the fore with us."

One of the largest maintenance issues, he said, is damage being done to the adobe by birds. Large brown woodpeckers called the Flickers peck at the soil mortar that holds the bricks together, creating holes that European starlings nest in.

"The state says it's tried fake owls (to scare off the birds) and all sorts of things, but none of it seemed to work," Sales said.

While pondering the problem, the group called in a restoration expert who specializes in adobe rehabilitation to do a quick evaluation. It lead to a surprising revelation.

"The first thing he commented on was that the Adobe was unusual in that it didn't have a coat of plaster on the bricks to stop the birds from pecking at them," Sales said.

Then, local historian Katherine Rinehart unearthed some old images of the Adobe that predated its restoration by the state in the 1950s. The pictures, one from 1880, show that the Petaluma Adobe, like most other adobes in the state, was originally plastered and painted over in whitewash. It appears that the state, for unknown reasons, must have removed the remaining plaster when it restored the building.

The group then found a report in a Berkeley library backing up its findings that the walls had originally been plastered and whitewashed.

"It was sort of a 'Eureka!' moment," Sales said. "It's begun a process we're really excited about."

So, he said, "We met with the state and showed them our findings, that the plaster was used to keep birds away and this was actually what it used to look like."

"Not only will (the plaster) do a better job of preserving the building, we now have new information and a better way of interpreting the building," he said.

But many steps remain before any plaster can be laid on those historic walls. First is a building assessment required by the State Historical Office of Preservation. Then the group must get the needed approvals from the state.

So far, however, the group says the state parks department has encouraged it to pursue the project.

Based on an initial assessment, the restoration project could cost between $280,000 and $350,000.

The group will begin fundraising for the first stage, the formal assessment, at an event at Lagunitas Brewing Co. in February.

Once a plan is in place, the association will likely pursue state or federal grant funding to help pay for the project.

In addition, the association is fundraising so that it can commission a study on updating signage and other interpretive elements at the Adobe, many of which have been there for decades.

"The displays are looking old and tired," Sales said. "There's all sorts of new technology that could make the building and site more interesting. It's an opportunity to dust off, remove the cobwebs from this wonderful building."

(To see documentation of the Adobe's original appearance, visit this link to the Library of Congress: http://www.loc.gov/pictures/item/ca1106/)