How to Hide Masonry Patches: Solving this Common Restoration Issue in the Field [Part 1]
The Ansonia, located along Broadway in New York City’s Upper West Side, is a magnificent, intricately detailed building that runs an entire city block and stands 17 stories tall. Completed in 1903 and constructed of granite, terra cotta and limestone. Today it’s a 385-unit condominium that’s being restored, which is where I stepped in.
The contractor (IGH Restoration) did a fantastic job patching the stone from a technical standpoint, but the color of the mortar patches stood out from the surrounding stone. It’s not an uncommon problem, so we fortunately had a Cathedral Stone Products solution.
How does a problem like this occur and how can it be fixed?
There are many reasons why a patch’s color stands out from the substrate, such as the natural variation in the color of the stone, the challenges of color matching to a cleaned substrate, and when a prior coating cannot be completely removed. The Ansonia had the added challenge of being on the National Register of Historic Places. Its specifications (such as colors and materials used) require an agreement between the building owner, the architect, and New York City’s Landmarks Commission. Contractors are limited in the colors they can use -- including mortar.
Even with the best planning, you can’t control how a patch will appear on one section of stone versus another, or how colors will appear in comparison when placed on different types of stone. Our recommendation – and the ultimate solution – was to create a stain by diluting one of our Potassium Silicate Coating colors with our clear Liquid Silicate —using more or less Liquid Silicate determines the overall opaqueness and translucency. Once you have the desired color and opaqueness/translucency, you can coat the patch with a closed-cell sponge to blend the color.
Patching is a labor-intensive, costly process, so this type of coating that can be matched to the surrounding stone prevents the worst-case scenario: removing and replacing the patches.
Can you prevent this problem?
With so many color variations in the stone itself and the condition of the stone, it’s very difficult to prevent it entirely. In my next post, I’ll give you some tips on how to reduce the number of discrepancies between the mortar color and the surrounding stone. It’s on my mind a lot as I drive down Broadway and past the Ansonia. The results are so satisfying to me. There’s additional restoration work in progress, but I can see that it will be a restoration centerpiece. It’s an example of what can be done when it's done right.
The After Photo
Work is ongoing as of this posting, but I will be sure to stop by and get an after photo to add to this post very soon.
