Plaster

Lime Plaster

Lime plaster is a traditional wall finish made from limestone that has been fired and then slaked, a controlled rehydration process that transforms quicklime into a workable material. Long before modern gypsum and cement plasters existed, lime was the primary material used to finish interior walls and ceilings throughout Europe and early North America. Its chemistry allows it to remain flexible, breathable, and compatible with historic masonry, qualities that modern materials often lack.

One of lime plaster’s greatest strengths is its ability to breathe. Unlike cement-based or acrylic finishes that trap moisture, lime allows water vapor to pass through the wall assembly. This vapor permeability helps regulate interior humidity, reduces condensation, and allows buildings to dry naturally. In older structures, particularly those built with stone, brick, or timber, this breathability is essential for preventing decay, rot, salt damage, and mold growth.

Lime plaster is also uniquely well-suited to historic buildings because it works with the structure rather than against it. Its natural flexibility accommodates subtle movement in walls caused by seasonal changes, settlement, and temperature fluctuations. When cracks do occur lime tends to crack softly and sacrificially, protecting the surrounding masonry rather than stressing it. In conservation work this reversibility and forgiveness are not flaws, but defining strengths.

Beyond performance, lime plaster offers an unmatched aesthetic depth. Its natural mineral content produces a soft, luminous surface with subtle variation and texture that modern plasters cannot replicate. As it cures through carbonation, slowly reabsorbing carbon dioxide from the air, it develops a living surface that continues to mature over time. This process not only strengthens the plaster but also reconnects the material to its original source: stone.

For conservation and restoration, lime plaster isn’t chosen out of nostalgia. It’s chosen because it preserves the long-term health of historic buildings, respects original construction methods, and ensures that repairs remain compatible, repairable, and honest. When properly applied, lime plaster doesn’t just finish a wall, it sustains the building itself.

Haired lime plaster on a barrel vaulted ceiling during a recent restoration project

Reinstating a wall after renovations at St. Pauls Church in Nantucket, Ma

George Washington's Tomb

During the recent restoration of George and Martha Washington's Tomb, Pen Austin, Henry Orton, and I carried out extensive replastering following damage to the roof system and ongoing drainage issues. Prolonged moisture infiltration had led to widespread deterioration of the interior plaster, as well as the wood lath and framing behind it. Once the damaged materials were carefully removed, the underlying structure was repaired and stabilized, restoring a sound substrate for the new work.

New lath and nailers were then installed to match the original construction approach, and the walls and ceiling were replastered using a traditional two-coat lime plaster system. This work restored both the visual integrity and the breathability of the interior surfaces. Throughout the process, emphasis was placed on material compatibility and the long-term health of the structure, allowing the space to dry, breathe, and age naturally without placing undue stress on the historic fabric behind the finished surface

Part of the ceiling started to delaminate and upon further investagation nail and wood rot was found leading to the need for larger repair

George and Marths sarcophagus were left uncovered after surfaces were striped and allowed to dry out prior to reinstating the lath and plaster

The the first or scratch coat of the new plaster being applied

After the second and final coat was applied, the work space was ready to be dissassembled and opened back to the public

Georges Washington's Bedchamber

During the Mansion Revitalization Project, Phase 2 included the complete re-plastering of the walls and ceilings in the Washingtons’ Bedchamber, Mrs. Washington’s closet and store room, the little passage, and the back stairway. Modern plaster and metal lath was carefully removed, documenting each layer and the conditions throughout the process.

With the walls open, the team was able to examine the original structure in remarkable detail. Dendrochronology confirmed that the framing timbers were felled in the spring and summer of 1774, and most of the 18th-century wooden lath was still intact. With the plaster removed, several important discoveries came to light: Evidence of a small 18th-century fire was found at the juncture of the north wall and ceiling, just above the mantel. Fragments of early plaster and a piece of 19th-century moiré wallpaper were uncovered on the ceiling and preserved in Mount Vernon’s collections. Original shelving configurations in Mrs. Washington’s closet and store room were confirmed through physical evidence. A fully intact 18th century fork was discovered inside a wall cavity in Mrs. Washington’s closet, supporting its historic use as secure storage for silver and valuables.

Wood repairs and new locally riven white oak lath was installed, and a traditional three-coat lime plaster system was reinstated. After the new plaster cured, the Preservation team restored the room’s finishes using hand-ground linseed oil paint and traditionally installed, hand-block-printed wallpaper and borders. Paint analysis of the woodwork identified several generations of paint from the 1775–1799 period, revealing far more detail about the wall finish history than previous analyses.

Old injection repairs where plaster had delaminated were found throughout the hall way were the most traffic is seen

Expanded metal lath was covering all of the wall surfaces over the orgional 18th century lath

An odd stretch of the hallway had plastic behind the metal lath and modern gypsum plaster

Delamination between previous plaster repair coats

The orgional wall lath was reused and damage peices were replaced with ones salvaged from the ceiling. All ceilings were replaced with new riven white oak lath