 any historic masonry houses in Charleston are clad with stucco. Stucco used on masonry buildings before 1830 was
lime- based and applied in a relatively thin coating. Over time, this type of stucco, containing lime and sand,
will break down into a sandy consistency and will need to be replaced with a compatible stucco mix.
 An HCF crafts training student learns stucco techniques
Stucco can lose its bonding ability over time. Water infiltration is the most likely cause of failing stucco.
When this occurs, the stucco actually pulls away from the masonry substrate, leaving a void or pocket between
the two materials. This is called "sounding." A simple test of tapping the stucco can confirm this problem.
If there is a hollow sound when tapped, the stucco probably needs repair or replacement.
Guidelines for Stucco Repair or Replacement
- Repair existing stucco only with stucco that matches the strength and finish of the original. This includes close attention to the overall texture and color of the original stucco. For example, historic stucco should be trowled for a smooth finish, rather than "floated" or "sponged" which creates a textured appearance by bringing aggregate to the surface.
- Retain as much of the original stucco as possible.
- Never stucco masonry that shows no evidence of previous stucco applications.
- Replicate the original scoring or tooling pattern as closely as possible.
Additional Resources
Preservation Brief #22, "The Preservation and Repair of Historic Stucco" by Anne Grimmer. |
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