Heavy Masonry Mortar Repairs are Possible With the Support of Forms
When facing a large and deep repair, such as the delaminated bluestone here, a mason’s first thought might be to apply the repair mortar in layers due to the weight of the repair. Perhaps that’s how they were taught to do it or how they’ve always done it — not realizing that with each layer they increase the likelihood of a repair that will fail.
The size of the panels in the photo below are quite large. Because you’ll want to complete each panel in one step, the repair will be heavy. In such a case, we advise using a wooden form to support the weight. So in cases like this, you can repair large, heavy panels in a single lift — saving on labor and not risking multiple layers not bonding.
For this project, the contractor used Jahn M160 Bluestone to the full depth of the repair, which is the ideal method for a lasting restoration. We’ve seen contractors use multiple materials to build out to the surface, but this attempt to come in at a lower budget lays the groundwork for potential failure. Only later will they discover that the exterior mortar layer and the materials used underneath are incompatible. That outcome is so common that we will cover the downfalls of incompatible restoration materials in a future post.
Until then, keep in mind the benefits of wooden forms for restoring stones to their original profile, especially when faced with a large and heavy and seemingly daunting repair.
Questions: contact me at tech@cathedralstone.com
