Cast Stone Removal and Preservation for First Methodist Church, Olvera St.

The church was declared unsafe when decorative masonry components began falling off the facade. As with other older structures in this condition, scaffolding was erected to protect pedestrians passing below.

As with many older structures, the decay was traceable to the rusting and decay (“ironjacking”) of interior reinforcing and structural steel components.

Evidence of previous repairs and other attempts to arrest the decay process were found throughout the facade.

Decay was found not only in decorative cast stone elements, but also in the flat, non-decorative cement stucco areas.

Careful removal of the cast stone entry units began at the top and proceeded down the side of the building. Basic principals of controlled removal were followed, as shown by this image, in which the artisan is removing grout from a joint to relieve stress on the edges of the cast stone unit.

Heavier pieces were lifted out using hoisting methods that date back many years.

After the cast stone units were safely removed, we then proceeded to remove approximately 2,000 sq.ft. of cement stucco from the adjacent structural concrete walls to complete exposure of all possible locations of failed steel reinforcement. Any cracks in the structural concrete wall could then be identified and injected with epoxy adhesive.

Single element cast stone decorative items were left in place.and reincorporated into the overall decorative scheme.

Cast stone units were stored at the site to avoid movement and possible damage during shipment.

This also allowed the area to function as the restoration studio, with cleaning and repairs of damaged pieces taking place on the site.

Cleaning involved the use of a mild alkaline-based neutral cleaner to remove accumulated soiling and carbon. Note the plastic-lined capture basin to ensure that all runoff and rinse water is collected for proper disposal. Getting rid of runoff from restoration, cleaning, and abatement procedures is a crucial part of a responsible preservation program.

Many hours were spent formulating the correct patching repair mortar and mix design. This involved numerous test samples, each requiring several days of cure time before the color and texture could be objectively evaluated.

While much of the patching repairs had to be hand-tooled, some mortar installation relied on simple wood forms to help determine the final shape.

Re-installation of cast stone units involved the installation of new stainless steel anchors systems, to avoid the problems associated with the original iron reinforcement.

Torque wrenches were used to ensure proper installation of the expansion anchors in the concrete backup wall. The red splotches are indicative of the anti-corrosion treatment applied to the ends of steel reinforcing bars in the concrete, to reduce future rusting.

Installing overhead pieces of the voussoirs in the arch involved teamwork and careful construction of falsework supports.

Pieces were lowered onto supporting units with stainless steel rods in place, ready to tie the component units together.

Final touches included the installation of matching grout in the joints between cast stone units. Note the tape installed at the edge of each joint, to prevent ‘bleeding’ or staining of the historic surface by the newly installed mortar.

The facade is now appropriately restored and stablized, and ready to greet parishoners back to the birthplace of Goodwill Industries.