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Restacking the pinnacles

Re-heading a gargoyle


Buttressing the buttresses

Restacking the pinnacles

Several pinnacles were shaken off their bases, including the four main ones atop the central tower. Masons discovered that only mortar and gravity had held some stacks of stones together. When the mortar cracked, they came apart "like a big game of Jenga," said chief stone mason Joe Alonso. Repair will require rebuilding some from the inside so that the stones will stay together.

A vertical rod likely will be inserted through the pinnacle’s brick core and into the huge stones below.

Smaller pins and dowels will run diagonally, joining one stone to the next.

Large stones that form each tier of a pinnacle’s base will be joined with metal cramp anchors that work like big staples.

Re-heading a gargoyle

Several ornamental creatures fell or lost parts, including a gargoyle whose head came off. Because the head is intact, several pins will be inserted through it into the body and epoxy will lock it back into place.

Carving new ornaments

Masons are replacing damaged carvings on otherwise salvageable stones, such as this crocket from the base of a pinnacle, with "Dutchman" patches. Some of the work is being done in place on top of the central tower.

1. The area around the damage is cut out in a block shape.

2. A new block is inserted with pins and masonry epoxy.

3. A stone carver creates the new crocket.

Buttressing the buttresses

All six buttresses around the apse on the east end cracked at the joint where the arch meets the freestanding pier. Engineer Jon Tung said there are two basic options that would help the buttresses withstand another jolt.

An issue of access
In many areas, Alonso said the problem is not only how to repair the damage but also how to reach it. Tung said the flying buttresses present a particular challenge because lifts can’t carry people or heavy equipment 90 feet up. The answer may be in massive scaffolding, pulley systems, pricey machinery, or all of the above.

Rods or pins could be inserted diagonally through stones. This method was used in some buttresses, however, and they cracked anyway.

A cable or steel rod could be threaded through the entire arch and tension would keep the stones together.