to cover with sheet iron in ridges & gutturs
let the ridges be 6. I. high & 5. times that in span=30 I.
then the slope will be 16.15 and adding 1.85 I. for the lap the sheets of iron must be 18. I. wide
consequently 18 I. of sheet clears only 15. I. horizontal, and if the sheets cost 18. D. the square, the cost of a horizontal square will be as 15 I.:18 I.::18 D.:21.6 D
(note the thickest tin is 18. D a box of 100. sheets 16¾ by 12¼=142. sq. feet the thin tin is 18 D a box of 225 sheets 14 I. by 10 I.=220. sq. feet.)
method of doing it.
place your joists 30. I. apart from center to center. let them be …
Notes and Drawings … Iron for Ridges and Gutters, 30 September 1804
Patrick Lee’s Explanation
Every leader needs some escape the pressures of work.
This excerpt, atypical for Jefferson Leadership Blog posts, is a different look inside the mind of Thomas Jefferson. It is a small segment of a lengthy list of measurements and directions for fabricating new iron ridges and gutters for the roof of his beloved home.
A leaky roof was a continual problem at Monticello. So was a convenient water source for a home located on top of a hill, distant from springs and rivers. Eventually, a new roofing and gutter system minimized both problems, effectively shedding the rain from the roof and collecting it in cisterns. These notes may have been been part of Monticello’s evolution from both leaky yet water-deprived to dry but water at hand.
Take a brief look at the full text, available through the link above. Like me, you will probably understand very little of it. Also like me, you might be impressed at the complexity and specificity of his mind.