Following the blind - until now
During the summer of 1992, while assisting the Pueblo of Zuni stabilize the old stone masonry homes in Middle Village, I was struck by the need to develop a method for underpinning buildings that would provide the necessary mechanical support and not damage the nearly thirty feet of archeological and religious deposits beneath. I had actually begun “inventing” the needed system when I discovered that I had been beaten to the task by a blind Irishman a hundred and fifty years earlier.
Alexander Mitchell, the Irishman, developed what he called the “screw pile” as a means of anchoring lighthouses in mud, sand, and similar unstable formations. The screw pile soon came to be known as the “helical pier” and has been in widespread use world wide ever since. The applications of helical technologies are practically endless: they are equally effective at holding things back as at holding them up and so are used as tie-back anchors for leaning walls; they can be installed in spaces as small as the chamber of a kiva fireplace; their bearing and tension capacity is remarkable— even the lightest pier we install will handle a load of 25 tons and, importantly in places like Zuni, the pier does not displace the soil, can be removed as easily as it is installed, and does not need bolstering with concrete or additional steel.
Within a few months of discovering them, I became a certified helical pier installer and distributor. Bummer that my bright idea had been hijacked by a blind man a century and a half before, but I still saw the potential for developing new hardware to accommodate a niche industry— the stabilization of buildings constructed of soft materials like adobe, and buildings of any description that had been built without a foundation or on collapsible soils.
In pursuit of solutions for underpinning buildings whose footings have absolutely no span strength, I invented “adobe baskets.” In response to adobe buildings whose walls had become so coved at the base that collapse was imminent, my son Jess invented “adobe cages.” Both are structural elements that can be supported with helicals. Along the way we began solving seismic retrofit problems using the piers in conjunction with polypropylene strapping to tie buildings off in controllable blocks. In short, we embarked on a period of creative thinking that provided elegant, efficient, and affordable solutions to structural issues in historic buildings. We found that improving on a brilliant idea with a specific goal inmind is almost as satisfying as inventing the core technology. Ah, but to have had that first patent...
It was a logical progression that the solutions we developed would have applications in contemporary settings. By the early 2000s, we were underpinning far more non-historic buildings than historic ones. The reason for that is many-fold: buildings are being permitted on marginally buildable sites; owners and architects are often loathe to spend money on a geotechnical assessment (or ignore the recommendations presented when they do); and contractor error and shortcuts are a major contributing factor as is the failure of inspectors to demand compliance when shortcomings are found.
In the last twenty-five years, we have installed thousands and thousands of helical piers inmany hundreds of locations in three states and Great Britain. And that’s enough. We have followed the blind man’s lead as far aswe care to take it, and are very satisfied with the results. We at Crocker Ltd have decided that henceforth we will no longer take on helical pier or moisture-remediation jobs unless they fall into a special category. We emphatically will retain and conduct our preservation business, and use piers and solve moisture problems in that context. In short, we will be limiting our services to buildings that are historic, architecturally important, or that demonstrate particularly difficult technical challenges.
We thank our long list of clients and colleagues, as well as the legacy of a visionary Irishman who gave us the hardware to begin.
Ed Crocker’s company, Crocker Ltd., specializes in the restoration of historic buildings and important architecture. The company has won numerous awards from the National Trust for Historic Preservation, the City of Santa Fe and the State of New Mexico. Ed is a Fellow of the International Council on Monuments and Sites. More information can be found at crockerltd.net