We have a new building-inspection rule in New York, as of last month, requiring annual inspection of parapets on pretty much all buildings. (Well, all buildings that have parapets.) Unlike the FISP program, these inspections do not have to be filed, merely the reports retained by the building owner in case the Department of Buildings asks for them; the inspectors do not have to be design professionals, simply someone knowledgeable about construction. Honestly, I do not expect to be asked to perform many of these inspections, if any at all, unless conditions are so bad that we would have been hired even if the new rule did not exist.
Parapets are funny things. They’re not structural even when the walls are, since they generally support nothing but their own weight. No matter how well built they are, they age faster than the walls below because (a) they are exposed to water infiltration on both faces, (b) they are not adjacent to heated interior space, so they tend to freeze all the way through in the winter, and (c) on buildings without roof access (which is to say, most buildings) damage may go unnoticed for a long time. In short, even at well-maintained buildings, parapets are likely to be in worse condition than the facades as a whole.
The picture above, a New Law tenement in Upper Manhattan, shows the original street-facing parapet on the right and a newly repaired side-wall parapet on the left. The bubbly surface on the old masonry is painted tar, which is great for waterproofing…for a little while. Then it dries and cracks, developing openings that admit water, and as it peels off it destroys the masonry underneath by ripping the face of the bricks. The use of regletted cap flashing, the presence of the old capstones, and the presence of the old waterproofing at the base of the new brick tells what work was done: the inside-face wythe of brick was removed and replaced.
