Andrew is restoring Toronto's Old City Hall, resetting, repairing even replacing some of those old sculptured blocks that sit high up on the wall.
One of his challenges is making mortor that will act and look like the original stuff. One way that he accomplishes that goal is to grind up whatever he cannot save and sift it into a fine old sand. This becomes the base of his restoration mortar.
Colonial Building Restoration from Scarborough, Ontario specialises in jobs like this. For critical information about working with mortar in both hot and cold weather, click here.