Eastern Columbia Building
Los Angeles, Los Angeles County, California
Restoration of Glazed Polychrome Terra Cotta Veneer
The Eastern Columbia Building is of one of the iconic facades of the LA landscape. Completed in 1929 in a distinctive Deco style of glazed blue-green terra cotta, it began life as a department store before going through an all-too-common cycle of multiple alternative uses before redevelopment as housing in 2005.
The upper portions of the building facade displayed widespread glaze failure, especially at the clock tower. As with many masonry failures, this decay mechanism was related to moisture directly related to the intrusion of moisture and rain. Alkaline salts deposited on the bisque surface are irrefutable signs of moisture migrating from the interior masonry backup wall. As the moisture forces its way out of the substrate, it 'pops' or spalls the impervious glazed surface during its escape.
Repairs of this type of damage began with preparation by 'feathering' or smoothing the sharp edges of failed surface glaze. This helped to identify sound material and to eliminate sharp edges for the application of surface coatings. While it would have been much more cost-effective to engage in wholesale removal of the original glazed surface, the tenets of Historic Preservation dictated that the maximum amount of original surface should be retained. We generally try to use repair mortars pre-colored to the palette of the undamaged facade. Thus, when the repair coating ultimately fails, the exposed repair material will at least mimic the color of the original.
The Eastern Columbia Building has evolved to its next life as a center for stylish residential living in downtown Los Angeles and as a symbol for the future of architectural preservation in our community.
Wikipedia link: http://en.wikipedia.org/wiki/Eastern_Columbia_Building
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The Art Deco facade of the 1930 Eastern Columbia Building was clad in glazed terra cotta, but material failure due to moisture penetration required that significant repairs be made to this historic facade. |
The highly decorated ceramic veneer used a turquoise palette for most of the surface, with gold highlights to magnify the visual effect. |
The upper portions of the building facade displayed widespread glaze failure, especially at the clock tower. |
As with many masonry failures, this decay mechanism was related to moisture. Here, the whitish alkaline salts deposited on the bisque surface are irrefutable signs of moisture migrating from the interior masonry backup wall. As the moisture forces its way out of the substrate, it 'pops' or spalls the impervious glazed surface during its escape. |
The extent of damage was directly related to its proximity to the top of the structure, again directly related to the intrusion of moisture and rain. |
Repairs of this type of damage began with preparation by 'feathering' or smoothing the sharp edges of failed surface glaze. This helped to identify sound material and to eliminate sharp edges for the application of surface coatings. |
Here, a prepared area is ready for the application of repair compounds and coatings as needed. Note that the porous grout lines seem to define the likely areas of glaze failure, a not-surprising indication of moisture penetetration into the porous grout lines. This moisture then migrates through the bisque clay of the substrate and forces its way out wherever the glazed surface will give way. |
Here, a prepared area is ready for the application of repair compounds and coatings as needed. Note that the porous grout lines seem to define the likely areas of glaze failure, a not-surprising indication of moisture penetetration into the porous grout lines. This moisture then migrates through the bisque clay of the substrate and forces its way out wherever the glazed surface will give way. |
Since the rough bisque body had been exposed, it was necessary to first coat the repair area with a thin-bodied repair mortar to fill the rough and exposed surface. We generally try to use repair mortars pre-colored to the palette of the undamaged facade. Thus, when the repair coating ultimately fails, the exposed repair material will at least mimic the color of the original |
Orbital sanders were used to smooth the repair mortar prior to the application of the final coating. |
In more detailed areas, hand-sanding was required for surface preparation. |
Suspended swing staging was used to gain access to the majority of the facade, but fixed scaffolding was required for the clock tower. |
Swing stage access can offer a much wider range of access, but it limits the amount of personnel per given area of building. This limitation of efficiency is usually acceptable when compared to the cost effectiveness of the system compared to fixed scaffolding. |
At three corners of the structure, there were decorative terra cotta screens that had endured severe deterioration over the years, again due to moisture penetration and migration. This image shows the planned location of stainless steel spiral anchors intended to 'stitch" the masonry fabric together again with mechanical anchors. |
Here one of our craftspeople is driving the stainless steel anchor into the terra cotta substrate using the vibrating installation tool to make a 'friction' fit. This method is advantageous on several levels: it is cost-effective, rust-proof, and requires no adhesives. |
The acute angle of pin insertion allowed this simple method to provide resistance to multiple directions of stress. |
The clock tower area of the building is the most well-known area of the structure and has undergone a dramatic change from its previous incarnation. |
The Eastern Columbia Building has evolved to its next life as a center for stylish residential living in downtown Los Angeles and as a symbol for the future of architectural preservation in our community |