What the heck is sneck harling?

Sep 29, 2015

How do historic stone structures like the 1690 manor house at Spencer-Peirce-LittleFarm in Newbury, Massachusetts, survive centuries of New England weather? Sometimes an extra layer of protection can help.

In the late 1990s and early2000s, the east end of the manor house was covered with a lime-based protective coating known as harl.Harling is a traditional practice for covering stone structures, widely used in Scotland and other parts of the BritishIsles. Essentially a type of stucco or parging, harl is a sacrificial weatheringlayer that is easily renewed.

First, irregularities in the surface of a wall arefilled with small stones in a process called galleting. In the next step, known as sneck harling, the surface is covered with a mixture oflime and sand. After these denser layers are applied, the surfaceis covered with several coats of lime wash or whitewash. The whitewash iseasily renewed when it begins to weather, which keeps the stones and mortarprotected from deterioration.

The harl on the manor house at Spencer-Peirce-Little Farm has been re-treatedtwice, once in 2009 and again in spring 2015. These regular maintenance activitiesare an integral part of traditional building practices. They protect thecore of the structure by renewing weather-facing materials before the innerlayers are exposed.

Please consider helpingHistoric New England maintain historicbuildings with a gift to the PreservationMaintenance Fund.