Brownstone was a popular building material in the mid to late 1800’s in the Northeast part of the country. Unfortunately brownstone does not hold up well to the effects of wind and rain. The photo below shows the underside of an exterior brownstone stairway at a building in Boston’s Back Bay neighborhood. The years of deterioration are also evident by the pile of brownstone powder on top of the fuel oil tank located under this stairway. Photo by Dennis Robitaille of Able Home Inspection.