Chimney repairs at Spencer-Peirce-Little Farm
January 5, 2011
Historic New England recently completed repairs to the north chimney of the main house at the Spencer-Peirce-Little Farm in Newbury, Massachusetts. The house is an unusual seventeenth-century masonry structure with a cruciform plan and multiple stone and brick chimneys.
Work included the removal, by hand, of all loose parging from the top of the chimney to the “shoulder” where the stack flairs outward, a distance of about six feet. The original parging was scratched with chisels to provide a bond with the new parging. Mortar joints were re-pointed with a lime-based mortar, then the parging, also made with lime, was applied in two coats.
Historic New England uses a traditional lime mortar, which exhibits the characteristics necessary to allow masonry to breathe and is soft enough to allow the surrounding masonry to expand and contract without damage to the bricks around it.
In addition to work at the top of the chimney, the stone base was also selectively re-pointed and repaired. Finally, the team installed a new chimney cap constructed of lead-coated copper. This new cap was placed directly on top of the old concrete cap and pitched to shed precipitation and prevent penetration of moisture into the chimney stack.
A construction technique used to finish a masonry surface, usually a wall or chimney, and can be applied over new or existing masonry. It is similar to stucco, but uses a masonry-based mortar rather than a traditional stucco mixture. Parging is also used as a noun to describe mortar mixture itself which provides a water resistant and protective coating to the masonry beneath. Though parging today often contains Portland cement, traditional parging was made of lime and sand.