Chapter 1: Metal roofing in history

Chapter 1: Metal roofing in history

The history of metal roofing is tied directly to the history of architecture and metalworking itself.  We find mention of building codes and metalworking in some of our earliest cultural relics. The Code of Hammurabi prescribes strict archaic penalties for the builder in the event of a failure.  In 2 Timothy, the apostle Paul introduces us to his enemy, Alexander the Coppersmith. In fact, an honest assessment of the human story reveals much value is placed on a culture’s mastery and knowledge of metal works.  Entire ages of civilization are named by the alloys that gave rise to their prosperity. 

We have some famous accounts of metal roofing in antiquity that most web guides cite: 

  • 300   BCE: Loha Maha Paya temple, in modern day Sri Lanka
  • 27      BCE: The Pantheon, Greece
  • 1280   AD: St. Mary’s Cathedral, Hildesheim. 

Our best example and longest surviving specimen of metal roofing is on the palace at Acchen. It is estimated some of these sections date back to the year 800 and are still functioning to this day. The methods those craftsmen used to join the roofing pans together did not include solder. All edges were directly seamed together with a hammer and anvil. For this to happen and still allow for water to flow over the seams is a process very akin to tailoring, and less to roofing.

One standing seam is installed, and then beat down out of the way. Another connecting seam is then installed on-top of that laid-down seam. Once the top seam is folded, it is then beat down so the connecting seam can be picked back up and once they are both standing, the un-folded edge can be folded with hammer and anvil to complete the connection. This is a tedious process that requires an experienced hand to keep from cracking the material, or destroying it in the process of seaming. This process, repeated on every seam intersection, will allow the whole roof to expand and contract without stressing any individual “pinned” or “glued” detail. The seam holds the sheets together mechanically, and also allows for movement at the bottom of the seam where the sheets are free-floating.

The medieval examples at Hildesheim, and Acchen are designed and fabricated with methods that have stayed superior to all other roofing methods to this day.  Secondary schools in France and Germany now teach in public colleges that which was once secret guild knowledge of the smiths. The guild system, which developed during the Middle Ages, passed trade secrets from father to son- or master to apprentice. This same knowledge is now codified in their education programs, and professional certification institutions. These function like medical or bar associations.

Chapter 1:2 Guild system

Metal Roofing Bible