The Science Behind Fence Construction That Lasts
Putting up a fence isn’t as simple as chucking wood at the ground and connecting the thicker bits with thinner bits. Constructing a fence is a slow-motion arm wrestling match against the force of gravity and decay.
The key to solid fence construction is understanding the balance of forces acting on each piece placed. The posts to the slats to the joists all need to work in tandem to stay stronger longer.
Enduring Fence Construction
No fence lasts forever, but a well-constructed fence will last fifteen or more years. What contributes to enduring fence construction? A solid grasp of the forces trying to pull it down.
Fences face pressures from gravity, corrosion, exposure, and mechanical failure. Keeping a fence standing strong means reducing each of these pressures with best-practices and industry-leading techniques.
Our residential and commercial fences need to function for years while looking good.
Physics and Fences
Fencing materials face a multitude of forces that can be easy to overlook. Wind pushes against the slats, a force that must be countered by the posts. Posts need to anchor the fenceline against this pressure and also mitigate temperature variations.
The upward load-bearing characteristics of a post and the connecting fence need to be strong enough to resist the weight of the materials. The more space between posts, the stronger the material needed to avoid sagging over time.
For fulcrums, such as gates, additional reinforcement to counterbalance the outside pull is important to avoid sag and mechanical wear on hinges.
The tensile strength of slats, chainlink, or other material needs to be adequate to avoid sheering when impacted. For areas with high levels of morning dew, the fence also needs to evenly distribute weight across the entirety to avoid sinking in softer soil.
The following breaks down the forces that bear on each component of the fence and how proper construction mitigates each issue.
The seating of posts is incredibly important to provide them with adequate reinforcement.
Fence posts need to be deep enough to offset the lateral force of winds, the occasional contact, and creatures (human and other) that sit on top or climb over the fence. A commercial fence may also need to support the weight of cameras and additional security features.
The depth a post is planted matters based on the frost depth of the area. Deeper frost allows for deeper posts. When a post encounters the frost line it will heat unevenly between the top and the bottom which can warp wood and create strain. Metal posts generate heat more quickly and suffer a larger flux across the length.
Posts are seated on a gravel base to provide drainage of the water coming in from below ground. Setting them in concrete or gravel backfill gives them some room to absorb vibrations and also offers friction to grip the ground.
Finally, a sloped area near the visible base wicks water away from the seating and away from the fence in general.
Post material is a hotly contested subject in fencing circles. Steel posts offer longevity in some areas but wooden posts withstand damage better and, in the right conditions, weather more slowly.
The material for slats is less contested. Generally speaking, the choice lasts as long as repairs are made and weathering doesn’t change.
Slats face the forces of wind, sun, and weathering. Fasteners need to hold fast without creating pinch points that lead to cracking or shattering in high wind.
Chain link allows wind to pass through, lowering the overall tensile forces on posts. Chain link features a 30-year lifecycle and is easy to repair or replace in the even to damage. That said, chain link is also the least visually appealing fencing material.
Brick or masonry fences last even longer (50ish years) but also weigh considerably more. They need to be maintained more regularly to remove corrosive elements from the mortar. They also need reinforcement along the ground line in areas other than just the posts.
Vinyl fencing is a popular option that looks great and lasts a long time (40 years). Vinyl is cheaper than wood and looks great for residential and commercial applications. The sound dampening of vinyl and wood fences are great features for a busy neighborhood.
Vinyl slats offer components that are quick to replace but can’t be repaired or patched. Vinyl also resists corrosion and water better than any other material.
Wood fencing falls into the most expensive category because of its initial cost and shorter lifespan. Treated wood that is well-maintained will last 15-20 years but eventually weathers away.
Wood slats take and hold paint and stains well and are easy to maintain and replace piecemeal. Higher-end woods provide unparalleled beauty with their rich colors and grains.
The two biggest forces contributing to the weathering of fencing material are water and corrosion. You don’t need to live in an area with heavy pollution for corrosion to be an issue. Debris from roads and residue from exhaust settle on a fence over time.
This is why it’s worthwhile to have a yearly maintenance schedule to pressure wash or repaint a fence. Removing corrosion build-up keeps a fence looking fresh and also prevents years from being melted off the material’s lifespan.
For areas with a lot of moisture, fences need to get enough sun to dry thoroughly or need to be seated in ways that allow for proper drainage and runoff.
Groundcover plants, and especially vines or creepers, need to be watched and trimmed to avoid roots pushing up areas of the fence. Weathering is the main culprit of fence decay but plant growth can lead to buckling if the area isn’t cleared before installation.
Whether you are looking for a security fence for a business or a privacy fence for a home, you want lasting quality. When all of the elements of fence construction are considered, the resulting fence will stand strong.
We deal in both commercial and residential fences. Contact us for an estimate and availability.