Patching concrete without removing the source of deterioration. Replacing an entire masonry feature such as a cornice or balustrade when repair of the masonry and limited replacement of deteriorated of missing parts are appropriate. Using a substitute material for the replacement part that does not convey the visual appearance of the surviving parts of the masonry feature or that is physically or chemically incompatible. Applying waterproof, water repellent, or non-historic coatings such as stucco to masonry as a substitute for repointing and masonry repairs. Coatings are frequently unnecessary, expensive, and may change the appearance of historic masonry as well as accelerate its deterioration.
Examples can include large sections of a wall, a cornice, balustrade, column, or stairway.
If using the same kind of material is not technically or economically feasible, then a compatible substitute material may be considered. The following work is highlighted to indicate that it represents the particularly complex technical or design aspects of rehabilitation projects and should only be considered after the preservation concerns listed above have been addressed. Designing and installing a new masonry feature such as steps or a door pediment when the historic feature is completely missing. Creating a false historical appearance because the replaced masonry feature is based on insufficient historical, pictorial, and physical documentation. Introducing a new masonry feature that is incompatible in size, scale, material and color.