On the scaffold at Torrisdale

Four days of taking a window out and three of them spent not touching it. You rub the panel — soft pencil, detail paper, both faces — you photograph it in sections against a grey card, you number every panel on masking tape at the top edge, and you write down what the mortar looks like before you disturb any of it.

Then, on the fourth day, you cut the cement, ease the panel forward on a wooden wedge, and two people carry it down a ladder. It is the shortest part of the job and the only part where an eight-hundred-year-old object can be destroyed in a second.