While you may find that your fence posts are pressure-treated, that's only the beginning of what you should do to slow down the rotting process. While a treated 4x4 may last 10 to 25 years, depending on the wood, the soil, and weather conditions, following the simple steps below could double or triple that number.
Installing a wooden fence post to prevent rot involves setting it in gravel or crushed stone at least one-third of the post's length, allowing for drainage. Tamp the base firmly and slope the top away from the post to shed water. Apply a wood preservative to the post below ground level and cover with soil.
A pressure treated fence post can generally last 10 to 25 years.
The truth is, treated lumber can — and does — rot. I've witnessed it on numerous occasions, and I've had countless people send me photos of their own rotten wood with the same questions you're asking. Not only can treated lumber rot, but wood-destroying insects can eat it.
Pressure treatment helps protect wood from rot and insects with the help of high pressure and preservatives, helping to extend its life. Generally, pressure-treated wood can last anywhere from 10 to 40 years, depending on a few factors.
A pressure -treated post will last five to ten years in the ground without anything special done to it. For most construction purposes, the first line of defense against wood rotting is to keep it dry and away from soil contact.
Posts treated with low retentions of copper naphthenate had an estimated 65-year longevity, but lumber specimens treated to higher retentions of copper napththenate had lower average lives of 27 to 30 years.
When comparing fence post lifespans, the life of a galvanized steel post far outlasts its treated wooden counterpart. In some cases, galvanized steel fence posts can last 50 -70 years with little to no maintenance.
That does help, and it will prolong the woods life, but no treating solution will stand up to a CONSTANT attack from air and moisture. That happens at the ground level. With concrete holding the moisture against the wood, wood has no chance and will eventually lose the battle.
Ground-contact pressure-treated lumber can be used either above ground or in contact with the ground. Has twice the level of chemical retention and protection compared to above-ground treated wood. Must be used when lumber is less than 6 inches from the ground or has poor ventilation.
How much weight (roughly) can an 8-foot normal 4x4 hold standing straight up? About 5000 pounds.
If properly treated and installed, pine fence posts can last for 20–35 years; untreated pine posts might only last 3–7 years. chemical in the posts. When large numbers of fence posts need to be installed it is probably most practical to pound them into the ground with a hydraulic post driver, small end first.
Treated wood post in ground
A well treated post is supposed to last 50+ years without any significant rot and in well drained soil/sand, that is common.
Dig post hole so diameter of the hole is 3 times the width of the post (i.e., the hole for a 4” wood post should be about 12 inches wide). The depth of the hole should be 1/3-1/2 the post height above ground (i.e., a 6-foot tall fence would require a hole depth of at least 2 feet).
Rotten wood can be repaired. Start by removing the rotting parts from the original board or joists. Then, fill the surrounding wood area with a soft wood polyester filler or wood putty using a plastic putty knife. This material fills the void and cures to ensure strength and resilience.
Contact the Dump about Construction Waste
There may be a small fee you have to pay based on the weight of the load. This is one of the reasons why fencing companies charge to get rid of old fence posts, because they have to pay money to the city to dispose of them.
Fill with Gravel or Concrete
Gravel helps keep moisture from the fence posts, slowing the rot. Concrete can more sturdily set the posts, but the moisture in the concrete may collect and absorb at the bottom of the post, accelerating the very process you're trying to mitigate.
The depth of the post should be a minimum of ⅓ of the height of what's above ground. This means that if you want a 6-foot tall fence, you need at least 2 feet of the post to go below ground. If this was the case, you would need at least 2 bags of concrete per fence post, with each individual bag being a 50lb bag.
It provides a physical barrier to keep moisture away from the posts by allowing drainage. It can also provide additional support for posts, protecting them from sinking into wet soil and further preventing decay and rot damage.
Treated wood fence posts can last between 10-15 years, depending on the type of wood. Untreated wood fence posts often last under 5 years. Rotting, warping, and splitting are the most common damages on wood fence posts. Metal or steel fence posts last the longest, up to 25 years, with minimal maintenance.
The strength and durability of concrete fence posts are some of their main draws for most buyers, especially when considered alongside their exceptionally long lifespan. Concrete fence posts can last for up to 25 years, and all with a minimal level of maintenance.
Pressure treatment wood is known for its exceptional durability, as it enhances its resistance to rot, decay, and insect damage. Western red cedar are also highly durable due to being naturally resistant to decay and insect infestation.
Cedar's natural resistance will give it a life expectancy of 15-20 years. * A comparable fence made with spruce would have a life expectancy of 3-7 years. Do the posts need to be treated? No, tests have proven that dipping a cedar post in creosote will not affect the life expectancy of the post.
The strongest is fir. Pressure treated lumber is yellow pine. It depends on what you're doing If it's within eight inches to, or touching the ground it should be pressure treated.