ACL Project List

Treatment: Grouting

Injection grouting is used in areas where the gelatin treatment is not strong enough to secure large or heavy fragments.  Loose mortar and structural cracks receive a fluid injection of ceramic microspheres, fine quartz sand, a natural hydraulic lime (NHL 3.5) and water.

Prior to grout injection, the areas for treatment are cleaned with compressed air and water.  Afterward, they are dammed with cotton, leaving the injection openings available for the insertion of the syringe.  Once the areas are filled with grout, they are left to dry for curing, typically one full day.  Afterwards, the cotton is removed.

In most cases grout color does not match the original finishes or mortars, and fill/edging over the grouted area and cracks is used to tone aesthetic inconsistencies.  A palette of red, white, and yellow local soil is mixed to match the historic soil mortars and plasters.  Fills are slightly scaled back from the surface plane to clearly identify them up close.