Client: Roberto Petrucelli.
Architect: Roberto Petrucelli.
Location: Flushing, New York.
Technical details:
0.8mm mm "Graphite Gray" zinc by Rheinzink.
Double standing seams. Ventilated roof.
0.8mm mm "Graphite Gray" zinc by Rheinzink.
Double standing seams. Ventilated roof.
Roberto's house is a one family unit. It is built with passion and attention to detail. Of particular interest are the solutions incorporated to make it energy efficient.
Focal feature of the house is a bay window in the front, covered with dark zinc roof
Roberto, having previous experience with zinc, wasn't confident with his roofer abilities. Asking around for advice, he was directed to me.
When I came to his house, I could see that the installation techniques were consistent with somebody working exclusively with tar roofs; the zinc was installed on incompatible substrate and not in pair with the traditional way of welting one piece of the material to another.
We had a discussion about the details andabove is a sketch I made on the spot for illustration.
I promised him to build a text book example of a zinc roof.
Zinc roof, to be able to withstand close to a century of exposure, must be built in a way that is fundamentally contradicting the American way of doing things - ever and ever cheaper.
It is crucial the roofer knows the traditional - time proven ways of laying zinc. It also crucial that he won't revert thoughtlessly to details borrowed from somewhere else, be it from lack of experience, or from the desire to cut corners.
The pine deck should be solid enough to be able to hold the nails for many decades
The eave profile, drip edge. The invisible part of it has much bigger role than the visible part:
it prevent water sippage back, during snow time and also during wet and windy weather.
The zinc panels are folded into dog ears in corners, like bread pans. The dog ears are then tuck in and folded into the seams.
Anybody that cuts the panels in at seam junctions and ends, then caulk, or solder the cuts, have no faintest idea what he is trying to imitate.
Walls are usually porous. Flashing prevents water from seeping through the outer layer of the bricks and causing serious damage over time.
Flashing should be set in with mortar. Mortar lets the water to seep out. If the flashing is held with caulk, the water is trapped inside, turning the flashing into useless decoration.
Ooops... Too much red in the mortar.
The word traditional in context of zinc, means that experience gained during the last 200 years of its usage as roofing material is incorporate in all stages of the project. During periodof two centuries, there was plenty of time to do enough stupid mistakes, to learn from them what is appropriate while working with zinc and what is not.
Zinc is very reactive material and not a likely candidate for roofing. However, drawing from experience in usage of another sensitive roofing material - lead - combined with welting techniques borrowed from copper, the first zinc roofers struck on the right system quite from the beginning.
Zinc is very popular in Western Europe. Today 85% of all roofs in Paris utilize zinc. The vast majority of architects and property owners rely on this durable material, experiencing typical service life of over 70 years, with almost no maintenance.
The success of Zinc in Western Europe was not replicated in United States.
According to the US National Park Service web site:
"Rolled sheet zinc appeared in the United States in 1816, as roofing in New York and as downspouts and gutters in Baltimore. Though more than seventy houses in New York had zinc roofs by 1837, it was out of favor by 1840. The popularity of the material was cyclical in the next decades, never matching iron and steel with their various coatings".
It seems that the American roofing craftsmen, drawing on different set of professional experience than their European colegues, failed to replicate the techniques utilized in Europe. The results, visible in matter of few years, were sending very clear negative message, which takes a long time to be forgotten. Then the cycle repeats itself.
Today most of architectural zinc in US is marketed by Rheinzink and VM-Zinc. Together with the material, they bring European experts to conduct training sessions and seminars for local wok force.
However it is overly optimistic to expect from professionals to replace life life long experience installing slate, shingles and copper flashings, with alien techniques demonstarted during a crash course of three days.
My experience inspecting zinc projects, shows that basic errors are quite common.
