The Fence Post

         The Enemy: Rust                          The Answer: Zinc

Oxygen and moisture working on iron and its common alloy, steel, result in rust. When thinking in terms of the wire used for fencing, sometimes being number one is not always tops. A Class 1 coating for your mesh or fence is anything but top rate. Now think again about that coating. It can mean: this looks fine or it'll do. In the long run (or short run), it will not stand up to the ravages of

• air
• moisture
• abrasion

However, a coating of zinc reacts differently to these factors. As it corrodes. It forms a barrier or patina, running interference between it and the steel or iron that it is sheltering.

The Protector: Zinc

The Classes of Zinc Coating 

Class 1--lightest coating of zinc; widely available and lasts 2 to 11 years in non-coastal climates. (.28% zinc per sq. foot)

• protection drastically reduced in humid climates. (For the record, there is no Class 2.)

Class 3--heaviest coating of zinc; lasts 13-30 years, often must be special ordered (.80% zinc per sq. foot)

• however, in humid conditions, the coating may last at least 15 years with wider wire gauges lasting longer.

Zinc galvanization--a coating for mesh and fencing that lasts

After wires are either welded or woven into a mesh, the entire finished product is drawn through a bath of molten zinc (830°F.) This galvanization-after-weave or weld method (GAW) creates mesh that emerges with a thick coating tightly bonded to the wire. Each strand of wire is protected and more importantly, each vulnerable welded or woven area is thoroughly sealed. In some circles, this is known as "galvanic healing!" Officially, this is termed, cathode-anode protection.

More zinc = more protection. Delaying the time until rust sets in. So the more zinc per square foot, the longer it is until it rusts.

What is Friability

If something is friable, it is subject to the rubbing process that works on the surface of unprotected iron or steel, which offers no natural corrosion resistant patina. Friability describes the flaking and breaking apart of a solid substance.

So what are the benefits of a Class 3 zinc coating?

• Lowest cost over the long run
• damage resistance--the zinc patina guards the metal underneath
• cheaper than stainless steel
• consistent results
• longest life

What does the ASTM standard mean?

Seeing this on a product, such as for zinc coatings, shows that a company is adhering to a certain set of criteria for the quality of a product. These are internationally accepted guidelines, based on research, for the specifications of materials, products, and services as approved by a  governing board. (ASTM International was once known as the American Society for Testing and Materials.) Buyer beware: a company's adherence to these standards is voluntary.   

Other factors for deterioration:

                airborne sand and dust                            chemicals                                   salt                                 air pollution 

Some zinc facts:

Zinc is the 27th most abundant element in the earth's crust. 70% is mined, 30% recycled. More than 50% of this is used to coat steel and keep it from disintegrating.

Zinc is found in rocks, soil, air, water, the biosphere as well as in humans, plants, and animals.

Biology: organisms must have zinc to exist. For example, in the human body, zinc is important for cell division and is responsible for the function of red and white blood cells.

And finally, a short video:

Here's an example of zinc galvanizing in action:

The Gabion Way

Gabion baskets are an earth-friendly solution to erosion and create a visually appealing landscape design. Many people live in areas where gabion baskets are needed but are unfamiliar with them. Contemporary gabion baskets are welded wire mesh panels held together with wire spirals or metal fasteners to make a wire mesh basket. The baskets are placed in the desired location and filled with rocks, stones, shells, wood, or earth--just about anything that weighs them down. This fill anchors the gabions down while allowing rain to seep through. They are completely permeable.

The numerous and varied uses include commercial applications, parks, zoos, and residential landscaping:

Commercial use of gabions:

• Bridge abutments
• Retaining walls
• Land management
• Seashore protection
• Gully control
• Culverts
• Erosion control

I've even seen a restaurant using gabion baskets filled with seashells as a decorative wall.      

Parks and Zoos

• Benches
• Pathway definition
• Climbing structures for children
• Partition walls
• Landscaping walls for plantings

Why choose gabions?

• Durable for many decades
• Quick and easy installation
• Strong
• Environmentally aesthetic
• Use of on-site materials
• Varied ways of using gabions

Residential applications include:

• Retaining walls
• Benches
• Erosion control
• Plantings of shrubs, vines, etc.
• Walls or benches around trees
• Firepits
• Partition walls

And they're easy on the eyes

Since residential properties are usually on a smaller scale, you can choose different mesh openings and sizes. Many landscape designers plant greenery inside the baskets for a more earthy appeal. You can use baskets of many different sizes, thus creating interesting serpentine or angular pathways.

Some Gabion Details

The wire used for gabions is a zinc-coated welded wire. It is hot-dipped galvanized after the welding process which seals and protects the welds against corrosion. They also come in a black vinyl coated finish. These are ideal for erosion control or to enhance the beauty of your property.

The standard size mesh for commercial use is 11 gauge, 3” x 3” opening size, 36” wide in galvanized or black vinyl coated finish. The baskets are shipped flat but partially assembled for easy installation. They are available in 3’ wide x 3’ high. They come in 3’, 6’, and 12’ lengths.  For residential use, you can use a 12.5 gauge wire with a smaller mesh opening size of 1.5” x 1.5” in either finish. They are also offered in varied heights, depending on your specifications.

Fight Erosion with Gabion Baskets

As you are considering your next outdoor project, whether for a commercial establishment or a residence, gabion baskets are a great solution for stabilizing vast areas of possible erosion due to potential flooding conditions, providing definition to the landscape or just to have a sleek look on residential property.

A Quick History of Gabions

Gabions, originating from the Italian name gabbione, which means “big cage”, were used during the reign of the Egyptian Pharaohs and later in Europe during the Middle Ages. The Egyptians made them out of sedges--think bulrushes like Moses’ basket-- and filled them with sludge to stabilize the banks of the Nile River. The Europeans made gabions out of woven sticks and filled them with stones to fortify castles as well as for erosion control of river banks.

Photo credits:

Angled project: http://www.gabionbaskets.co.uk/

Serpentine project: http://www.minimalisti.com/

A Lasting Fence 

When you build a wire fence, the type of wire you use is very important. Using an inferior wire will lead the fence to rust quickly and need to be replaced. Instead, you should use vinyl coated, stainless steel, zinc aluminum with black paint (if available), or Class 3 galvanized (if available), which will stand up to the elements and last much longer. However, just as important as the type of wire you use are the type of posts that hold the wire up. These are often overlooked when it comes to fence building, but if you use the wrong type, it can weaken the structural integrity of your fence even faster than the wrong wire. That’s why it’s important, when building a Class 3 galvanized wire fence, to use galvanized posts as well.

• Galvanized: To galvanize something is to coat it in a protective layer of zinc. Zinc will stand up against water and the elements better than other types of metals, protecting against rust and making your metal last longer. Galvanization takes place either before (GBW) or after (GAW) the welding. GAW is the longest lasting of those two. Class 3 galvanized wire (if available). Class 1 galvanization uses only a very thin layer of zinc, which lasts 2 - 11 years before it rusts. In a coastal area, where salt water is a factor, it can last 2 years or less. Class 3 galvanization, on the other hand, is thicker and can last anywhere from 13 to 30 years. It’s a little more expensive, but it doesn’t have to be replaced nearly as often, saving you more money in the long run.

• Stainless Steel: Stainless steel welded wire mesh is strong and long-lasting. By its very nature, stainless steel wire needs no additional finish, such as galvanizing or PVC, to protect it. The wire itself is extremely resistant to rust, corrosion, and harsh chemicals. If you need a welded mesh or fence in an area with prolonged exposure to corrosives, stainless steel products will meet the demands. Type 316 is recommended for saltwater environments since it has a higher resistance to corrosion than Type 304.

• Vinyl Coated - VC: Welded wire fencing and meshes are both long lasting and attractive. Galvanized welded mesh is coated with a thick layer of PVC which is tightly bonded to the wire by a heat process. The coating is flexible and will not crack when the wire is bent. It is stable over a wide temperature range, maintaining its qualities in extremes of both hot and cold temperatures. UV inhibitors are in the vinyl to retard degradation from sunlight. The coating is also very resistant to scraping and abrasion. Vinyl coated welded wire mesh and fence sometimes referred to as plastic coated wire products, are very strong and durable. They are long lasting and rust resistant. They have double protection. Not only does the vinyl coating seal the wire from water and other corrosive elements, but the underlying mesh is also protected by a zinc coating.

• Zinc Aluminum - ZA: A new, zinc-coated aluminum hybrid coating. It lasts more than twice as long as Class 1 but uses less coating then Class 3, which saves you money.

• ZA with Black paint: Lasts more than twice as long as Class 3 and is painted black. It will last 13 to 30 until rust in non-coastal environments.

The Benefits of Steel Posts
The wire isn’t the only part of your fence that’s subject to the elements. The posts are as well. You can have the best wire on the market, but if the posts fail first, you’ll still have to replace your fence sooner than intended. A lot of wire fences use wood posts. They’re strong and sturdy, but they can rot over time, or be eaten away by termites and other bugs. It’s much better to use metal posts. The best posts are the steel T-posts because they are galvanized. They are made with studs every 2 1/8" down the length of the post, allowing you to customize the height of your fence easily and prevent the fence from riding up and down the post.

Galvanization is a plus--

Of course, metal posts are subject to the same issues as metal wires are. If you’re not careful, they can rust. Therefore, just as it’s important to use the choices mentioned above for your fence, it’s also essential to use galvanized posts. Galvanization will guard your posts against the elements so that they don’t rust as quickly.

Your posts are what hold your fence together, so it’s important that they be strong, sturdy, and long-lasting. A high-quality wire on a cheap, low-quality post will cause problems and likely need to be replaced within a few years. But if you use strong, metal, galvanized posts, with top quality wire, then your wire fence can last you for decades.

Harambe's End

It was an incident that shocked the entire world, with both animal lovers and parents everywhere flabbergasted by the outcome of something that could have been easily prevented. The Cincinnati gorilla killing occurred on May 28, when a 3-year-old child managed to climb through and fall into a herbivorous ape’s enclosure at Cincinnati Zoo, overlooked by the eyes of his mother. Despite her negligence in failing to monitor her son’s behavior, the mother was not charged and instead, Harambe the gorilla was shot dead. To add an even bigger element of shock to the tragedy, footage released after his death exhibited the ape’s seeming protective behavior towards the young boy. 

Enclosures that Protect

Following the death of 450-pound Harambe, who had celebrated his 17th birthday just the day before he was killed, investigations were demanded by animal rights groups, including Stop Animal Exploitation Now. Aside from the animal’s unfair end to life and the mother’s failure to know her son’s whereabouts, zoos everywhere are now wondering just how they can prevent future disasters such as this. So, what is the answer? To make sure structures are completely childproof.

Here are some ideas zoos may want to consider to ensure the health and safety of visitors at your wildlife park or zoological garden:

• Fences – There are so many fence designs and styles to choose from for safety purposes, including class 1 galvanized fences that are coated with a layer of zinc and class 3 galvanized, which are stronger due to their thicker coating. Heavy duty fences and vinyl coated fences will also do the trick.

• Hardware – Once fences have been installed, they can be strengthened with hardware in the form of earth anchors and ground staples. Consider this if the animals in your zoo are of a heavy weight or possess good climbing capability.

• Mesh and Netting – The options really are endless when it comes to selecting mesh and netting. For superior safety and rust resistance, hexagonal wire netting will be a worthwhile investment, whereas lightweight sparrow netting will work best for zoo enclosures with small animals, such as birds. Keep in mind that mesh can also be used to reinforce concrete structures.

• Welded Wire – Stainless steel, vinyl coated, galvanized before (GBW), galvanized after (GAW) – the choice really is yours. Used widely for the containment of large animals, welded wire offers security that is impenetrable, making it ideal for childproofing purposes.

Barrier Strategies 

Being a zoo owner/supporter means that you are responsible for ensuring that both adults and young ones are safe in their surroundings. Making a decision about which childproof structure would be best for your zoo depends on what animals you house in your enclosures. For example, tall structures should be strategically placed to prevent children from being able to climb over the obstruction. Chain link mesh barriers would be best suited to keep smaller animals in their designated territory, as would net enclosures. Speaking to a professional who can provide you with bespoke solutions will guarantee that your structures are childproof for the long haul.     

Here's a video which describes the incident above in detail:                                                                                     

Coatings: Researching Options

You’re all set to install a wire fence on your property. But what kind of coating will you use on the fencing material? It’s a question a lot of beginners don’t consider, but it’s an important one. The wire coating you use on your fence determines a number of factors, including how long it will last and how it will handle itself against the elements. So what are your options? Here are the basic types of wire coating for fences.

• Class 1 Galvanized – This is the most basic type of coating, used on barbed wire and field fences. The wire is galvanized, by adding a thin, protective layer of zinc. It’s cheap and efficient, but unfortunately not as effective as other types of coating in the long term. Class 1 Galvanized wire fences start to rust quickly. They’ll last a maximum of 11 years, and sometimes as little as 2 years. In a coastal area, where there’s salt water in the air, it can last an even shorter time.

• Class 3 Galvanized – This is a stronger, longer-lasting zinc coating. Whereas Class 1 wire coating uses 0.28 ounces of zinc per square foot, Class 3 uses a thicker coating of 0.80 ounces per square foot. It costs slightly more than Class 1, but it will last anywhere from 13 to 30 years before it rusts, making it well worth the investment.

• ZA – A relatively new development, ZA is a Zinc-Aluminum hybrid coating. It uses less coating than Class 3, making it cheaper, but the aluminum prevents rust, so that it still lasts about the same amount of time. The result is a less expensive wire fence that will still last you up to 30 years before it rusts.

• ZA and Paint – Paint on a fence does more than simply make it look more attractive. After galvanizing the wire with the Zinc-Aluminum coating, it’s painted with black polymer paint, which offers even heavier protection against rust and corrosion. It lasts
  even longer than a Class 3 Galvanized fence and protects against the harshest elements.

Vinyl – Also called PVC or UPVC coating, vinyl is the strongest wire coating of all when it comes to standing up against the elements. A thick, flexible PVC layer is added to the galvanized wire. That way, not only is it rust resistant, it also stands up to extreme temperatures, as well as UV rays and even physical abrasions against the fence. Plus, its flexibility means it won’t crack when the wire is bent. Generally available in either black or green, vinyl is the strongest, most durable, longest lasting wire coating you can buy. 

More Temporary Needs or Harsh Environments?

So which wire coating is best for your fence? It depends on what you need and where you’re located. If your main goal is cutting costs, and the fence only needs to be temporary, then you can probably get away with Class 1 galvanized wire. If you’re looking for something a little stronger, that will last longer and save you money in the long run, go with Class 3 or ZA. If you really want your fence to last a long time, then ZA and Paint is the way to go. And if you live in a coastal area, or one with other harsh elements, and want a reliable, long-lasting wire fence, then you’ll want to go with vinyl coating. Consider your needs and your options carefully. A well-built wire fence with the right coating can last you a lifetime.