The Fence Post

An Excellent Overview

Another excellent instructional video from the folks at Bekaert. Learn how to install barbed wire to make a safe and secure fence. A general overview of the process of getting that fence in place. High tensile wire means no stretching.

4 Foot Fences - Recommended Guidelines 

• Fences should be as long as possible.
• Install with a bottom gap of 6 in. under the fence.
• Steel posts should be on 8 ft. centers.
• End posts should be 6 ft. or less from the adjacent post and braced.
• Wood picket snow/sand fence should be pulled taut to at least 250 lb/ft.
• Synthetic fences should be pulled taut at tensions specified by manufacturer.
• Plastic fences should be sandwiched between two 2" x 2" boards wired tightly to the steel post at the center and at 6" from each edge.

The Height and Bottom Gap

• Height is the most important factor in fence design.
• It has the greatest influence on particle trapping efficiency, storage capacity, and cost.
• Adding 6 in. to a 4-ft. fence increases its capacity by 30%.
• Characteristics of the fencing material, such as porosity and size and shape of openings, are relatively unimportant.
• The gap between the bottom of the fence and the ground increases the height and capacity of a snow fence.
• The bottom gap reduces snow deposition close to the fence.
• A gap larger than 8" may be desirable in locations where the fence may become buried.

Posts and Tensioning

• Steel studded T or U posts can support wooden slat or plastic snow fences.
• Posts for a 4' fence should be spaced 8' apart.
• Posts must be designed to withstand wind loads, and allow proper tensioning of fencing materials.
• Plastic snow/sand fences require tensions as high as 250 pounds per foot of height.
• Posts at ends or corners should be braced longitudinally.
• Curved fence lines are undesirable - the tensioning forces tend to pull down the fence.
• The force that the wind exerts on a fence depends on the wind speed, density of the air, upwind topography and ground cover, and the height and porosity of the fence.

A Wooden Snow Fence

• Wood snow fence has slats 1-1/2" wide, held together with double strands of twisted wires.
• Porosity is typically about 60%.
• Available with red oxide stain or natural unstained finish.

High Tensile Plastic Sand or Snow Fence and Tensioning

• Most plastic fences, such as Nordic Plus II by Tenax, are made from black or orange polyethylene.
• Plastic fencing has high tensile strength, but it can be cut and is susceptible to abrasion.
• Fence must be well secured to posts.
• Fencing should be tensioned to the manufacturer's specification.
• End posts must be adequately braced to allow tensioning of the fence.

Information was taken, in part, from the Strategic Highway Research Program by The National Research Council. For more extensive and in-depth information about snow fences.

Supplies, Directions, & Handy Tips

Here's a video demonstrating how you can install field fence so that it's straight and will last a long time. See our other blog articles "How To Install Wood Fence Posts" and "How To Build Strong Bracing For Fences" for additional helpful information.                              

And! What you probably don't want--

Safety on the Roads 

A snow fence is a very desirable barrier for road and highway maintenance as blowing snow reduces visibility for drivers, blinding them and causing accidents through lack of vehicle control. Blowing snow also complicates the upkeep of roads. Unmanaged snowdrifts reduce visibility at intersections and curved roadways, increase the buildup of ice, bury signs, and reduce the effectiveness of guard rails and safety barriers.

Snow and Sand Fences - their effect 

Blowing snow particles are similar to tiny grains of sand. Those particles too heavy to be suspended in the air move by bouncing or intermittently jumping along the surface of the ground. The heaviest particles roll or creep along the surface, collecting into drifts or dunes. Snow and sand fences restrain the wind, acting as windbreaks and slowing its speed. This forces more of the suspended particles to fall to the ground and the creeping particles to come to rest. Some particles are also deposited on the upwind side of the fence. This drift is normally 15% of the amount captured on the downwind side.

Protecting the Coast

As sand dunes are a major buffer between sea and land, maintaining the dunes is a key to preventing coastal erosion. Not only do properly placed sand fences preserve dunes, but they can also divert foot traffic away from helpful dune-preserving plants such as cape beachgrass.

Drift or Dune Growth - the stages

Stage 1 - A lens-shaped drift forms as creeping particles are caught by the fence. The wind force diminishes for a distance equal to about 15 times the height of the fence. As the blowing snow or sand falls to the ground, the drift becomes deeper until the wind no longer follows its curvature.
Stage 2 - An eddy or recirculation zone forms at the downwind end of the drift or dune. The mass of the drift itself adds increasingly significant wind resistance which may improve the efficiency of the fence. A recirculation zone at the tail of the drift traps particles that blow off the top. The drift becomes deeper but not much longer.
Stage 3 - As the drift approaches its maximum depth (for 50% porous fences, 1 to 1.2 times the height of the fence) the recirculation zone at the tail end fills in as the drift lengthens downwind. This trapping efficiency declines as the recirculation zone diminish in size.
Stage 4 - When the downwind end of drift or dune begins to assume a smooth profile, the recirculation zone begins to disappear. Subsequent growth is slow as the drift approaches its maximum length.

Read our blog article "How To Install Snow & Sand Fence - Guidelines."

Information was taken, in part, from the Strategic Highway Research Program by The National Research Council. 

Some Very Serious Skills Here

How high should you build a fence to keep your dog from escaping? It depends on the fence ... and the dog! Some dogs are just smart, steely, and determined. Can any tall wire fence contain them?