Preservation Project Update #2

Restoration of the south porch masonry is finally underway!

In preparation for re-pointing, all of the old mortar has been cut out of the joints between stones.

The new pointing on this section of wall is complete.

Intact mortar like this keeps water on the outside of the wall.  This, in turn, protects the iron cramps which hold the limestone to the back-up wall.

When the iron cramps rust, they exert enough pressure to crack the stone.  This lets more water into the wall, which causes more rusting, and the cycle continues.  Spalls like those at left are the eventual result.

The masons have finished preparing all of the spalls for patching.   Just like filling a cavity in a tooth, it is important to remove all of the "decay" first.   Sometimes the damage is more extensive than it first appears.  This is the same section of wall pictured above.

There are also two mock-ups for the spall repairs in this picture.  Can you spot them?

The masons expect to complete this phase of the Preservation Project in 2-3 weeks.  I am eager to see what the south porch looks like once they finish!