Many people have written the SWI requesting help in assigning a financial value to stone walls. Unfortunately, there is no easy answer, and properly credentialed assessors have not yet paid much attention to the practice. In the mean time, and off the top of my head, I suggest the categories and methods show below. If you have information about this topic and are willing to share it, please contact the SWI.
For any situtation, a stone wall can be treated as a linear quarry with value based solely on the stone present. It is this “bare-minimum” value that is driving the strip-mining and stone-export business. All other values are destroyed when the stone is taken. The material value is determined by many factors, including geographic location, access, and the quantity and “quality” of stone. To determine this value, bring one or more masonry-supply contractors to the site and ask for an estimate of the value of the stone. (Of course, my recommendation is to leave the stone in place).
Bring one or more experienced stone masons to the site and have them estimate what it would cost to build a unit length of wall that resembles the one already in place. This price should include obtaining a mix of quarried stone that matches the wall, doing so without strip-mining an existing wall. Multiply the price per unit length by the total length of wall on the property. This represents a minimum value of the wall, because it does not contain subjective or intangible value.
This is the strangest stone wall I’ve seen, a mortared decoration along North Road in Jamestown, RI. To me, it has negative worth. But to it’s owners, or perhaps to the local historical society, it has great value. This means of estimating a wall’s value is strictly subjective because it involves intangibilities, including but not limited to: family history tied up with the wall, known historical connections, sentimental value, educational and aesthetic opportunities, and the intrinsic value of authenticity. In most cases, this method will likely represent a maximum value.
Historic walls have intangible value for their authenticity in the same way genuine antiques have higher value for their authenticity. In the furniture business, for example, there is both considerable experience in assessing the value of genuine antiques, and a clear market-based pricing for manufacturing and distributing antique reproductions. Hence, for any given class of objects, there exists numerical ratio between the value of the genuine article and the value of the reproduction. This ratio can logically be used as a multiplier to convert the value of a reproduction wall (see replacement value above) to the value of a wall in which the authenticity is still intact. Mathematically: R = Va / Vr where R is the ratio, Va is the average value for any class of antique ( furniture, vehicles, folk art, etc.) , and Vr is the value of the average value for reproductions of that class. Next: Vaw = R * Vrw, where Vaw is the value of the authentic wall, R is the ratio calculated above, and Vrw is the value of the reproduction wall (see Replacement Value above).
REAL ESTATE METHOD
Rural land in New England that is graced with abandoned stone walls has higher intrinsic value than land either without walls or denuded of walls. Have an experienced real estate assessor perform a market-based assessment the land that DOES NOT take into account any value associated with buildings, improvements, zoning, easements, etc. Next, have that same real estate assessor repeat the process while imagining that no walls are present on the property. The difference between these assessments will be the value of the walls for both their material value (if strip-mined) and their value based on authenticity/landscape integrity.
DOLLAR RANK OF METHODS
In my experience of having discussed the value of stone walls with many different stakeholders, the minimum value is MATERIAL VALUE. Next in sequence are REPLACEMENT VALUE, the REAL ESTATE METHOD, and the RATIO METHOD. The maximum is INTANGIBLE VALUE.