Copper chimney caps and stainless steel chimney caps can be fashioned in all shapes, sizes and styles by metal and copper work craftsmen. Chimneys can take on a whole new appearance with a custom chimney cap mounted on the chimney top, made from high quality pure copper or thick gauge stainless steel. Instead of a minimal afterthought, chimney caps can become an attractive focal point and provide additional architectural interest and elegance to fine homes and commercial buildings.

Chimney cap, chimney vent, chimney pot, chimney cowl and chimney shroud are all various structures on a chimney top added to the top of your chimney pipe, chimney flue, stove pipe or even chimney crown. The chimney crown is the flat top of a chimney usually finished with cement or mortar and is ideally sloped to shed water. A fireplace chimney is typically constructed from brick, clay, masonry, metal or fireproof material. Often times there is just a metal chimney pipe or chimney flue that is encased in a fireproof material or else is double wall insulated shielding adjacent flammable building materials. Chimney vents or stove pipe vents vent fireplaces, wood stoves and heaters and provide proper draft. The chimney vent opening might be nearly flush with the chimney crown or else the chimney pipe or chimney flue will protrude out. Stove pipe chimney vents are also found protruding out of the top of roofs. Chimney pots positioned on chimney tops, look like small smoke stacks and functionally extend the length of a chimney. Chimney pots may therefore improve a chimney's draft inexpensively. Whether it is a metal chimney vent, masonry chimney or chimney pot or other chimney material, there is a need to have some sort of termination or cap on the chimney top, to keep rain, birds and critters out of your chimney, chimney pipe or chimney flue. Without a chimney cap, rain water might run into your fireplace, stove or heater and additionally leaks from seams or cracks in the chimney might also damage adjacent walls and ceilings. Also build up of rain and moisture inside your chimney often produces a pervading chimney or smoky smell inside your home. Birds, raccoons, squirrels and other small animals might enjoy the warmth of your chimney, set up home there and clog it with their nests or bodies. So chimney caps often have screening, mesh or lattice work to cover openings. Chimney caps may also protect a chimney crown by shedding rain water and ice. Chimney caps with metal mesh or screening may also perform as a spark arrestor to protect adjacent roofing, walls and ground areas from sparks or embers that may exit from a chimney. Finally, chimney caps may also be purposefully designed to control, preserve or improve upon a chimney's draft. Many chimney caps are made of metal including stainless steel chimney caps, copper chimney caps, aluminum chimney caps and the ever common black painted galvanized steel chimney cap. Standard type chimney caps have a simple sloped roof to block most of the falling rain and mesh sides to block birds, small animals. Some employ tighter screening to also neutralize sparks. They are designed to simply clamp on to round, square or rectangular chimney flue pipes with screw fasteners. Round versions may also provide protection for exposed chimney pots. More expansive, elaborate chimney caps, such as chimney hoods or chimney shrouds, provide a decorative architectural feature and protect more of the chimney top crown.

Galvanic Corrosion is an electrochemical process which occurs when dissimilar metals are in contact with each other in the presence of an electrolyte, most commonly being moisture and oxygen. For example rain water and salt water make especially good electrolytes. An electrolyte could be any non-metal matter that will conduct an electric current and are predominantly liquids or moisture. Every metal has been rated for nobility and then placed on galvanic scales according to nobility. Basically nobility is a measurement of the resistance to corrosion, especially of one metal contacting another metal. Metals that are the least noble means they are very anodic, electropositive or high potential and will corrode most easily. Whereas metals that are the most noble, means they are highly cathodic, electronegative or low potential and will be the most resistant to corrosion. The most corrosive effects will occur between metals from the opposite ends of the galvanic scale or ranking of nobility. This difference in electrical potential between two or more metals causes galvanic corrosion. Dissimilar metals in contact with each other in the presence of an electrolyte causes current to flow through their points of contact at the expense of the metal with the higher potential or less nobility. The much less noble metal is gradually consumed in the Electro-chemical reaction and will deteriorate or wear away as the metal ions migrate away from the very anodic metal to the more noble cathodic one. The more noble metal's corrosion resistance actually increases from this transfer of ions to it from the less noble metal, while the other metal is gradually getting consumed. Below is an abbreviated galvanic scale showing ranking of the most common construction metals from the least noble up to the most noble in a normal construction setting where both moisture and oxygen are present.

Galvanic Scale (Nobility of Common Metals)*
Least Noble
Aluminum
Zinc
Galvanized Steel
Iron
Stainless Steel – Active
Tin
Lead
Brass, Bronze
Copper
Stainless Steel – Passive
Titanium
Most Noble

Electropotential of Various Metals
High
Aluminum     +1.30
Zinc            +0.76
Chromium     +0.60
Iron            +0.44
Nickel          +0.22
Tin              +0.13
Lead            +0.12
Copper         -0.34
Silver           -0.80
Platinum       -0.86
Gold            -1.10
Low

Since dissimilar metals in contact with each other in the presence of oxygen and moisture will result in the less noble metal being corroded or eaten away the more noble one, contact between dissimilar metals should be avoided. For example, copper as one of the most noble of metals should be kept separated from less noble metal such as aluminum and galvanized steel. If contact between dissimilar metals cannot be avoided, their surfaces should be insulated as much as possible at the least with a non-metallic, non-conductive coating, such as bituminous or zinc chromate primers or paint. Separating the dissimilar metals with tape, gaskets, waterproof membrane, sealants or other non-conductive material that does not absorb and hold moisture can be used effectively. Care must also be taken to avoid the liquid wash run off or discharge from the drains from noble metals to less noble ones. For example rain water run off from a copper roof going into aluminum gutters and downspouts will result in traces of copper salts in the run off wash accelerating corrosion of the aluminum. Additionally, the use of galvanized nails, screws, flashing or drip edge on copper roofing or copper gutters should likewise be avoided as such less noble fasteners and metals will corrode rapidly. While rain water is a good electrolyte so too is high humidity or moisture laden air especially when it contains a high concentration of corrosive acids as is typically found in larger cities or near industry. In industrial or heavily populated areas, harmful electrolytes are formed by the absorption of gases by rain and fog to form acids and salts, while in coastal areas a saline electrolyte is formed by the combination of salt with the moisture laden air.
 
As copper has one of the highest galvanic numbers or nobility of construction metals, copper will not be harmed by contact with any of the common metals. However, copper will promote corrosion of other less noble metals if placed in direct contact with them. Copper can be used most appropriately with lead, tin, lead-tin solder or stainless steel under almost any circumstance. The primary metals of concern in terms of galvanic corrosion contact with copper are aluminum and zinc. Large differences in the thermal expansion rate between copper and these metals may cause additional problems. Also avoid using copper and some brass fasteners with aluminum, zinc and most ferrous metal. Paints or coatings that are used for isolation must be compatible with both of the dissimilar metals. The bituminous or zinc chromate primers and paints can be used between copper and aluminum surfaces. These same coatings or a red lead primer can also be effective in separating copper from iron and the other ferrous metals such as galvanized steel or mild steels.

Another type of corrosion called erosion corrosion is caused by the flow of acidic water concentrated into a very small area. While especially true for the least noble and most corrosive of metals, but capable of affecting all metals, acidic water allowed to concentrate on a small area, for example rain water from a large area like a roof diverted towards a flashing, valley or gutter can cause erosion corrosion. Also acidic water or liquids pooling on metal surfaces or trapped without air circulation between roofing or sheathing can quickly corrode the metal. Solution is to eliminate such pooling, maintain air circulation underneath metal roofs or between inert roofing material and drip edge, valleys and flashing. Another solution is to use replaceable reinforcing insulative strips between the inert materials and metal. Raw zinc and aluminum especially are susceptible to prolonged contact with acidic moisture, as for example the underside of a zinc roof. But care should be taken even with copper and stainless steel. Copper and zinc possess a superior property in that both will gradually develop a long term protective patina that helps guard against such corrosive effects for a very long period of time providing initial safeguards are exercised such as drying out provisions or temporary coatings.


*Note: Galvanic chart rankings involving sea water immersion and low oxygen conditions will vary somewhat - the more typical nobility given here is for land based construction.

Re-using old guttering or buying cheap aluminum or plastic guttering are tempting options but may perhaps not be the best option. It is recommended you stay away from any kind of painted, rusted guttering or lead coated guttering for obvious health reasons if you are growing produce. Many plastics have unhealthy emissions and plastic gutters can also break down from the weight, UV sunlight and trowel work. It is best to use a gutter made from a pure metal that does not have any chemicals or paint applied, does not corrode or rust over time, is durable, long lasting, naturally weathers well, is aesthetically pleasing and is a genuinely attractive feature of your home. Steel and aluminum are relatively low priced but most varieties require some type of coating to resist rust and corrosion and coatings oxidize, scratch, are not durable, long lasting and mostly unhealthy too for a gutter garden. Galvalume is a zinc-aluminum coated steel that is a better candidate than either steel or aluminum alone, combining the corrosion and rust resistance of zinc and aluminum with the strength of steel but with an industrial looking gray metallic appearance and you would probably be tempted to paint this material. Three even better choices for your gutter garden are zinc, stainless steel and copper. Everyone is familiar with the appearance and attributes of stainless steel and it is a viable option. Stainless steel does not rust providing it's surface is not damaged and it is generally considered a healthy, sanitary material. Stainless steel's shiny appearance may be attractive or it may not blend in or complement your home's exterior. Pure zinc is a viable, healthy option that is durable, weathers well and zinc develops an attractive protective, grey patina that is somewhat pewter like though zinc is priced higher than galvalume and stainless steel. Then we have pure copper which may be the best choice for a multitude of reasons: copper has proven itself for centuries to be the most durable and longest lasting metal; copper weathers extremely well, forming a protective attractive patina; requires little to no maintenance; copper is attractive, aesthetically pleasing, elegant and complements most home decor well; copper is EPA approved antimicrobial, germicidal, antibacterial and fungicidal; copper is a key nutrient for plant life; copper is considered eco-friendly and is a green building material. These are all attractive and most desirable traits for use in your gutter garden. Copper although being our highest rated choice also has the highest initial cost of all the metals and metal alloys mentioned above. Copper's many and unique advantages, help justify it's premium cost, especially considering the relatively short lengths required for most gutter gardens, which put copper gutters' premium price within reach and affordability.


Once you have decided on the material for your gutter, you will then likely choose between three common styles of gutter: K-style gutter, half-round gutter and box gutter. A box gutter will give you the most volume with which to garden with, and as it's name suggests, it has a rectangular box appearance or if you like a plain box planter. K-style gutters are probably the most common residential gutters used in the U.S. and are somewhat boxy as well, though with a angled stepped front for a little more pizzazz. Half round gutters do look just like they sound, like half of a round cylinder or pipe and half-round gutters also have the most elegant appearance of all the various gutter types. There are also quarter round gutters which also are very attractive with their curved front. Quarter round and K-style gutters are generally available from 5 inches to 8 inches wide, half round gutters usually from 5 inches to 10 inches wide and box gutters are usually manufactured to size. Custom widths are also available through Rutland Gutter Supply.  Compare the different appearances of K-style, box gutters, half-round, quarter round and embossed gutters, all pictured below.

The need to prevent the spread of germs has always been a major concern. Research indicates that a copper surface is more effective at preventing the spread of germs than stainless steel. Copper has a 2000 year history of antimicrobial applications in a multitude of cultures. More recent research has sought to determine uncoated copper's effectiveness in stemming the proliferation of infectious disease. At the University of Southampton in the U.K. research studies have shown that many common disease causing microbes such as  E. coli, Aspergillus niger (black mold) and Influenza A, die within hours on copper surfaces. The Influenza A family of viruses includes the problematic Avian flu and swine flu strains and copper can help contain a flu. Even deadly antibiotic resistant bacteria associated with infections such as MRSA (Methicillin Resistant Staphylococcus Aureus) die within 1.5 hours on pure copper. On stainless steel and plastics, typically used for food-processing hardware, pathogens survived unabated for days, sometimes more than 30 days. There is enough solid evidence to put man’s oldest metal to work throughout the world to help protect us from infectious disease. Tested copper alloys, such as brass or bronze also offer increased protection over non-copper containing materials such as stainless steel, painted surfaces, wood and plastics, although not nearly as effective as pure copper surfaces.

Some fairly common and obvious uses in the home for elegant yet functional copper home decor include copper kitchen sinks, bathroom copper sinks, copper bar sinks, food prep sinks, copper basin, copper vanity sink, copper door knobs, copper handles, copper range hoods, copper planters, copper pot racks, copper bowls, copper sheets or copper tiles for making copper countertops and copper sink backsplashes, copper tabletops, copper chair arms, copper wall plates and switches, copper light canopies, copper ceiling fans, copper vents, copper louvers, copper cookware, etc. There are germ killing copper facades available for refrigerators, dishwashers, freezers, ice-makers, ovens and ranges. There are copper-plated kitchen appliances, copper vases, copper sculpture, copper accent pieces, copper planters, even copper flowers. Copper bathroom fixtures and copper kitchen appointments may be the most obvious places to most benefit from and utilize copper's antimicrobial power, yet manufacturers are now focusing in on all home furnishings and furniture as well as laptop, remote control and cell phone cases. The ceiling for new copper surfaced products is sky high, especially considering copper's aesthetic qualities, durability, long lifespan and green copper work as eco-friendly too.

For more detailed health information regarding the necessity of copper in the human diet and medicinal purposes, I will heartily recommend starting out with these two excellent articles: Copper and Human Health and Copper in Human Health.