Calculate How Many Fence Posts You Need For Wood, Plastic, Or Chain Link Fence
Once you determine the length of fence you need, you can calculate the number of fence posts required for a wood, plastic, or chain link fence. Spacing between fence posts will depend on the height of the fence and type of fence construction. Metal fence posts for example are typically spaced farther apart than wood fence posts due to their superior strength.
1. Calculate Wood Fence Posts:
- Height matters when it comes to wood fencing. As a general rule of thumb, the taller the wood post the shorter the span between posts. A 6-foot-tall fence having 2 feet below ground encased in concrete, should have a span of 8 feet between post while a ten-foot-tall fence with 3 feet of the post below encased in a concrete footing should have a span of 6 feet between posts. Use the fence post calculator to calculate the number of posts needed for your fence once you determine the heigh and length of the fence.
2. Calculate Chain Link Fence Posts:
- Stronger than wood, chain link fence posts can be spaced farther apart than wood posts. For example, a 5-foot-tall chain link fence would typically feature post spaced 12 feet on center. However, in cases where fencing is unusually tall, like a chain link fence that surrounds a schoolyard for example, metal fence posts are spaced much closer, typically 8 feet or less. Chain link fence posts are almost always supported by poured concrete footings.
3. Calculate Plastic Fence Posts:
- Relatively new to fence building, plastic fence posts are lightweight, durable, relatively strong, last longer than wood posts, require no maintenance such as painting. Unlike metal chain-link fence posts, they are available in a variety of colors and two profiles: round and square. Like wood and metal fence posts, plastic fence posts should be set below ground using concrete footings. Post are spaced farther apart (about 10 feet) for low rise plastic fencing compared to the 6 feet between posts requirement for high rise plastic fencing.
4. Spanned Fence Posts Calculations:
- Relatively new to fence building, plastic fence posts are lightweight, durable, relatively strong, last longer than wood posts, require no maintenance such as painting. Unlike metal chain-link fence posts, they are available in a variety of colors and two profiles: round and square. Like wood and metal fence posts, plastic fence posts should be set below ground using concrete footings. Post are spaced farther apart (about 10 feet) for low rise plastic fencing compared to the 6 feet between posts requirement for high rise plastic fencing.
Fence Post Calculator
Fence Post Calculator
Fencing off the perimeter of an acreage is viewed as a necessary expense, accepted by farmers as just another cost of doing business, which is typically a write off at tax time. The last 30 years or so, near 80% of all fence posts have been manufactured of metal leaving just 20% wood most of which are coated with environmentally damaging preservatives. Other than penning grazing animals and accumulating drifted snow as a water source for the spring, fencing serves no other purpose, creates no additional revenue, degrades over time and required periodic maintenance.
An alternative to using preservative soaked fence posts is to plant a living tree in it's place: it is environmentally sound, costs less money, costs nothing to maintain, creates a windbreak and potential for revenue.
Living Fence Posts
Tree seedlings are selected by type and growth rate determined by first the time it takes to grow to fence fastening capability and the type of biomass that can be grown for the market. Use the fence post calculator above to calculate the number and type of tree seedlings needed to enclose the perimeter of a given property with living fence posts.
Living fence posts create an opportunity to earn income from each tree growing along your property lines. Depending on the market, fence trees should be chosen for their coppicing ability: the ability to sprout new trees from a cut trunk. Hybrid poplar, basswood, willow, and paulownia are excellent candidates for living fence pots.
Fence To Revenue Timelines
It takes about 5 years from the time of purchase and transplant before the trees are sufficiently strong enough to support a section of rolled metallic fencing using the 3 tree examples mentioned in the previous paragraph. The first year after the rolled fencing is attached, each living fence post is topped, about a foot above the fence line. Topped tree material can be sold as the first biomass crop.
Note: It is important that fence trees are topped in the spring, just as the sap begins to run and the buds swell on branches. This will ensure that new trees have sufficient nutrient to sprout from the cut stump.
This new growth, called coppicing, will grow between 3 and 10 new trees depending on the species of tree, which will grow 2 to 3 times faster than the original tree because of its developed root system. In 3 to 4 years, it is ready to harvest and will grow a crop 3 to 10 times the size of the first one thanks to coppicing. After harvest, the cycle begins again and continues for the life of the tree, which can extend beyond 100 years or more.
Use the fence post biomass calculator below to calculate revenue generated by the total number of fence posts growing poplar, basswood, paulownia, or willow tree biomass.
Calculate Potential Revenue From Coppicing Biomass Fence Posts With The Fence Post Calculator.
Fence Post Biomass Calculator
Tree Plantation
Plant A Living Fence As A Windbreak
If the coppiced growth is not harvested for biomass, then it will quickly grow into an extremely effective windbreak that would be almost impenetrable to the wind even in the winter. The exposed lower fence line stretched between the trunks of the tree posts could be fitted with vertical fencing to break the wind with the added benefit of accumulating snow in drifts inside the fence line for spring melt water.
Another alternative is to plan and set your living fence inside the perimeter border of your property 30 feet or so, then plant a continuous row of evergreens about 20 feet outside the fence but still within your property line. By the time the living posts are ready for attachment of the metallic fencing, the evergreen border will be grown enough to block the wind from blowing through the wire fence.
Making Adjustments To The Living Fence As The Tree Grows
The need may arise to adjust a few wire fence connections to tree posts from time to time. As a rule, living fence posts may grow in height through years 6 and 10 but only slightly, perhaps 1 or 2 inches, which will lift the fence line a little. Anymore than that, the fence may have to be lowered and re-attached, which would only need to be done once as the tree will stop growing vertically along the height of the post and begin to increase diameter instead. If you're using invisible wire as barely seen in the image below, periodic adjustments are not required due to its flexibility.
