I’ve been meaning to update the site with better organization. Robert’s question and this discussion about seamed pipe boots was the motivation I needed… There are a lot of videos on Youtube, but they are mostly in foreign languages and even alphabets, making a search for trad roofing techniques very difficult for english-speakers. I’m starting to compile the best videos on a new page here: https://tradroofing.wordpress.com/how-to/
Here’s our discussion from the Trad Roofing forum and the video another member of the group submitted to help with his journey: https://youtu.be/w7lAFq7j3qg
There is very little information in english on traditional metal roofing. This is what prompted me to begin studying seaming, and publishing the metal roofing bible in 2018 after years of study and work in this field. I found all of the American resources lacking in this department, and most of the leaders in the field of historical roofing in America lacking in their knowledge of time-honored methods for folding and seaming. This short brochure is one of the few examples that show basic seaming techniques.
Although it does not offer instruction on how to create patterns for unique situations, it gives the reader the basics of the “knots” used to accomplish different details in metal roofing without cutting, soldering, or sealants. These techniques allow the roofing elements to be free-folded, and more importantly it allows the roof to be repairable in the future without disrupting the entire assembly. This is not possible with american flat-lock methods where pans are soldered together creating a monolith.
The Anaconda Copper Mining Company, part of the Amalgamated Copper Company from 1899 to 1915, was an American mining company. It was one of the largest trusts of the early 20th century and one of the largest mining companies in the world for much of the 20th century.
The specs here are for 10oz copper, what they call “economy” roofing. I assume from the title, the marketing, and the specs it was offered less to promote permanent roofing, and more to sell copper. We would never use 10oz copper for a roof.
Right away, we are treated to incomplete information, and oversimplification… showing transverse seams. It gets worse on the next page…
Fixed clips can only be used on short rafters. (less than 28′). When you join the pans together with the field seam it creates columnar strength that essentially makes it a single pan. This is the hard lesson learned by those in europe who were tasked with replacing their own failing designs. The roof works against the fixed clips and eventually works them out, causing a wholesale failure over about 200 years. While this would be a decent life-cycle for most, we are striving for better and we now have the knowledge to do better. A general rule of thumb: if you are creating a copper roof that needs more than 2 10′ pans, incorporate expansion clips. Further: the roof needs a fixed point in the middle, for low pitches, and higher up the roof depending on pitch. This is to account for “critical loading” where the weight of the roof itself starts to bear on the clips and fasteners as the pitch increases. For a steep roof: the fixed clips are placed almost near the top, with expansion clips below.
So what’s wrong with this? Several things: the rules dictating the use of transverse seams are completely reliant on the pitch, and overflow/backflow conditions. Further they don’t demonstrate what the rules are for creating the notch. This is covered with more clarity in a modern resource:
Even with these rules of thumb, it’s important to realize other factors can determine the use of a wide-notch transverse seam at low pitch.. It can only be used in un-obstructed field where there is no risk of overflow.
A few pages later, we see some very simple hip “instructions” showing dead-cut full seams with no notching. It was possible to fold a light-gauge steel roof with no notching to the pattern, but it’s not recommended. Anyone who has attempted to fold 6-8 layers in copper knows this.
While I was excited to see a reference showing the actual folding of hips and ridges, this ultimately does not help the installer create a permanent assembly as it could be with the proper planning, and care to joinery. It is better than Neubecker’s treatment of standing seam, but only gets us about halfway there.
This goes to demonstrate the main issue with knowledge of metal roofing in America. We assume that historically: they knew what they were doing but our references compared to similar work and knowledge from the old world shows this is not the case.
The author is a Hungarian roofing engineer, Laszlo A. Santo.The owner of his own roofing company, who educated more than a dozen master roofers.
In his book, the author, relying on his forty-year professional experience, after ten years of computer development on the topic, offers the readers attention to the basic nodal connections of traditional roofing works on metal, carried out in digital form and put into practice. In the four-volume edition you will be able to get acquainted with the key connections of the work carried out, the prescriptions of professional rules and practical experience, supplemented by a collection of instructions, lectures and articles. Each volume is devoted to a separate topic, but they are all closely interrelated. This edition will be interesting, of course, to roofers, architects, designers and other market participants, working with both metal and small-piece roofing.
Volume 1. Roof water discharge, linear coatings, structures
Suspended roof gutters and gutters 7 – 65
Eaves and hidden, recessed gutters 66 – 160
Covering walls, overhangs for soft roofs and parapet gutters 160-210
Protruding designs and decorative details of the roof 210-300
Volume 2. Metal parts for roofs from small-piece materials / elements
The skills of surface development pattern making are important for decorative sheet metal, historic preservation, metal roofing, and copper work. Learning how to develop a pattern for any shape you would like to create can be useful for larger architectural forms as well.
One of the techniques used in pattern making is called “parallel line development”. This skill is vital for creating notching patterns for standing seam roofs.
The book, along with many other primary sources are hosted at The APT Library at the internet archive.