Bandelier’s Alcove House Restoration Presents Challenge

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Monument > Vanishing Treasures staff is developing a plan of attack

By Arin McKenna

 The kiva at Alcove House has been an iconic feature of Bandelier National Monument since its creation in 1916.
“I would identify Alcove House as one of the signature experiences for Bandelier National Monument. It’s very unique. It’s not an experience you’ll find at other parks,” Bandelier Superintendent Jason Lott said. “It’s been one of the core experiences since the park was established.”
Now concerns about the structural stability of the kiva has prompted park staff to close the feature to insure visitor safety.
Restoring the kiva has been on staff’s radar for some time. Bandelier’s Vanishing Treasures division conducted an in-house condition assessment in 2010. An architectural firm and engineer were hired in the fall of 2011 to develop a design for the stabilization work and the project funding was obtained before sequestration set in.
The project took on a level of urgency on April 10, when Vanishing Treasures staff was conducting an assessment for the stabilization work and discovered that a significant chunk of masonry had come loose and that the structure was being undercut. The kiva is perched on the edge of a 140-foot cliff, reached by climbing four sets of ladders, so the threat is significant.
“There’s a risk to our visitors that we could have a collapse on it, and depending on where they are, it could result in them coming of the cliff, or in visitors on the trail below being injured by the fall itself,” Lott said.
Vanishing Treasures Program Manager Sarah Stokely is overseeing the project, with help from exhibits specialist Rachel Adler and technician Jonathan Holdsworth. Adler explained the project.
The first stabilization and restoration of Alcove House occurred in 1910, with the last major reconstruction occurring in 1965. Early stabilizations kept the original structure, a very cylindrical shape with a small cylindrical air shaft attached to it. Only a small portion of the top of the kiva was visible above ground.
A hundred years of erosion from wind, rain and human footsteps has eroded the soil and tuff (soft volcanic rock) to below the level of the kiva.
During one restoration, a retaining wall of cement and rock was built to protect the original walls and hold them up. But the cement masonry makes the stones to deteriorate, so now some sections have cement masonry blocks with no stones to hold it up.
In assessing the most recent damage, staff also discovered that the outer wall has become detached from the inner one, allowing water to flow between the walls and erode the foundation.
“So this outside wall is basically suspended by the top few courses of masonry. As you can see, it’s not being supported by the ground,” Adler said. “We’ve been told by engineers that have come to look at the site that it’s no longer serving a structural purpose, so it’s no longer supporting the roof of the kiva, nor is it supporting the original walls that are underneath. So all it is doing right now is adding extra weight and pulling on that original structure.”
The plan is to remove the outer wall, then assess and restore the original one.
“It would return the kiva to more of what it looked like originally,” Adler said. “The iconic photos that you see of it, of people going into and out of the kiva from the 1910s and ‘20s, the structure looks way different than it does now. So I think it would be a good way for Bandelier to kind of connect to the history of that site.”
The roof is another issue. The 5-inch vigas (roof beams) are not made to support the weight of 20 to 25 people–which it is frequently called upon to do when groups pose for photographs.
“The vigas have a lot of flex in them, so the roof sort of acts as a trampoline. There’s a lot of flex in it and that causes a lot of outward force on the walls,” Adler said. “So that, in conjunction with all this heavy weight and rubble–there are a lot of complex issues that need to be taken into account altogether.”
The plan is to lay plywood over the beams to more evenly distribute the weight. That will be masked by treatments to make the roof look historically appropriate.
Once the restoration of the kiva is finished the next phase begins.
“We need to take a hard look at how we’ll be able to manage how people experience the site, so they get a full and rewarding experience, but so we don’t have to sacrifice the safety of the site or the visitors or the resources in that process,” Adler said.
The plan is to combine landscaping and education to direct visitors away from vulnerable areas.
“The visitors aren’t doing these things to deface the site or to vandalize. They just don’t know,” Adler said. “If they consider their impact times 300,000, or however many visitors are going up there, that adds up. So I’m a firm believer in education being the best tool you can use to get visitors to do what they need to do and what you want them to do.”
A retaining wall will be built up around the kiva to take the brunt of erosion.
Strategically placed boulders, yucca and cholla cactus will discourage walking on the wall. Landscaping to improve visitor safety is also part of the plan.
The most challenging aspect of the work will be getting 8,000 to 11,000 pound of materials to the site for the kiva restoration, and hundreds of thousands of pounds for the retaining wall.
“We can’t bring a crane down there. It’s not realistic to think we’re going to pack that in: it’s mortars and rocks and all kinds of stuff,” Lott said. “So they’re being very creative with cables and they’re being very creative with aircraft, helicopter slingloads in particular. And I will say Rachel has a strong back as well.”
Lott is currently assessing whether it will be feasible to open Alcove House this summer, although the kiva will be off limits until restoration is complete.