There are many different types of wood lumber and grades available at your local home improvement store so it is important to know the important items when purchasing the materials for your repair.
- Pressure treated posts should be rated for ground contact – AWPA grade UC4A for general purpose or UC4B for heavy duty.Avoid peeler cores when selecting 4” x 4” x 8’ fence posts.
- Pressure treated fence rails should be AWPA grade UC3B if left unpainted, grade UC3A if painted or finished with an opaque stain. 2×4 rails in 8-foot lengths are commonly used.
- Nails, screws and other fasteners used with pressure treated wood should be double hot dipped galvanized or stainless steel; ASTM A 153 Class D
When a storm blows through the wind loads on your fence can be incredibly high and all of that load is transferred onto the post. You can work through the calculations of ASCE/SEI 7-10 yourself, or just know that it is important to select the strongest building materials available.
Pressure Treated Lumber
Pressure treated lumber is chemically treated to inhibit fungal growth and insect activity. The three common types of pressure treatment are ACQ (alkaline copper quaternary), CA (copper azole), and the newest type is MCQ (micronized copper quaternary). There are different grades of pressure treatment and proper selection depends on the severity of the location and how the wood will be exposed to the elements.
When we consider the privacy fence for most homeowners, the fence post is the most critical element. The post bears all of the stress from wind gusts and is exposed to moisture and insects underground that can cause the post to deteriorate and weaken. Wood fence posts should be pressure treated and rated for ground contact.
What about cedar posts? The quality of wood coming out of the lumber mills has declined significantly over the past 20 years – it used to be that you could get old growth heart wood (from the center of the tree) that would last for decades as a post, but today the quality is simply to variable to recommend using cedar or other naturally rot-resistant wood. Most of the trees brought into the mill are from 10-year re-growth and the posts will contain very wide rings from the sapwood layer that simply will not last.
How Long Will a Treated 4×4 Post Last in the Ground?
Not all wood is the same; even 4x4s that come from the same mill and have the same treatment can have dramatically different life spans when put into a demanding application such as holding up your privacy fence.
There are three main factors that will determine the life of your post: the strength of the wood, how well it accepts the pressure treatment chemical, and how well the post is protected from moisture.
The Strength of the Wood
First, eliminate any posts that have excessive knots – especially if they have included bark. The knots lower the lateral strength of the wood and the included bark diminish the integrity by allowing easy access for moisture and insects to the interior of the post. Most importantly check the end grain of the post. You want to select rings that are close together. The denser the rings, the stronger the post and the longer it will last.
Of course, an oak post will last longer than a pine post, but we are not talking about the species of wood here. Most pressure treated lumber is either pine or fir so when you walk up to the stack of lumber, which post do you pick out?
You want to avoid the center of the tree – it contains the pith, which is the youngest wood in the tree. The pith is weak wood because its job is to grow vertically very quickly and be flexible. Posts made from pith are more likely to warp, twist, bow, and splinter. You want to select posts with end grain that are tightly spaced from the middle part of the trunk because it is the heartwood that provides strength.
Heavier Does not Equal Stronger
What about weight? Won’t the heaviest post be the strongest because it will be denser wood? This is true for kiln dried dimensional lumber – a heavier piece typically means a tighter grain structure and stronger wood. But kiln dried wood has a moisture content between 5-10% and it doesn’t affect the weight much from piece to piece.
The pattern is for pressure treated lumber to be sold very wet, almost to the point of dripping. A significant amount of the weight is actually water weight. If you buy a wet post and then let it dry for a year, you will find that it will be many pounds lighter than when you bought it.
How Well the Wood Accepts Pressure Treatment Chemical
Different manufacturers use different pressure treatment chemicals but the common ones are alkaline copper quaternary (ACQ), copper azole (CA) or micronized copper azole (MCA). These treatments cause copper to bond with the wood fibers to slow decay. They also resist other factors that promote rot and structural degradation like termites, fungus and moisture.
Chromated copper arsenic (CCA) was used to pressure treat lumber until 2004, when CCA was phased out by an agreement between the EPA and lumber industry. Later studies showed that while arsenic leached in higher amounts from CCA treated wood, the ACQ treated wood leached a greater amount of copper. The takeaway for homeowners is to use a dust mask when cutting treated wood and take steps to mitigate any leaching into your vegetable garden.
Whenever you are buying pressure treated posts make sure that you get wood that is rated for ground contact. Ground-contact pressure treated wood has twice the preservative and is required for applications within 6 inches of the ground, with poor ventilation, or where it will be difficult to maintain or replace – these are all true of a fence post. This is commonly listed as AWPA grade UC4A; the preservative retention requirements are listed below:
ACQ retention of 0.40 lb/ft3 (PCF)American Wood Protection Association
CA-B retention of 0.21 lb/ft3 (PCF)
CA-C retention of 0.15 lb/ft3 (PCF) under the Wolmanized brand
Note that the MCQ pressure treatment method has not been rated by the AWPA standard.
To ensure your fence will stand for 10 years or more without worry the best method is to use pressure treated 4” x 4” pine posts that have the proper AWPA grade of UC4A. For severe locations that hold moisture, such a low-lying areas or where there is heavy clay soil with you may choose to go with UC4B grade posts for extra rot resistance at a higher cost.
Most stores will carry #2 grade pressure treated posts rated for ground contact. The lumber grade is different than the pressure treatment rating, #2 lumber is used when appearance is not too important. Make sure that green post is really ground-contact rated!
We previously covered how the pith is weak wood, another reason to avoid the pith is that it does not accept the pressure treatment chemical well. Because the chemical doesn’t absorb the pith wood will rot earlier.
When the lumber mill makes plywood veneer they spin the log on a lathe and cut off the thin veneer. Just like unrolling wrapping paper, at a certain point they can’t peel any more and are left with the core. It is common for many of the 4×4 posts to be made from ‘peeler’ cores that you don’t want to use fence posts.
What is a Peeler Core?
The peeler core is a byproduct of plywood production but the mill won’t let anything go to waste so they turn them into 4x4x8 posts. The peeler cores contain the pith, which we just learned is the weakest part of the wood that doesn’t accept the pressure treatment chemical.
Examine the picture – both of the top posts are peeler cores and should be avoided. The bottom right post is a little better, but you can tell that is still close to the center of the tree. The bottom left post is the best of the group, it is from farther out from the center of the tree away from the pith. Generally, the flatter rings that are spaced close together will give the strongest post and the best value for your money. Ideally you want to find posts with end grain similar to the photo below.
Avoid the Bulls-eye
Now you know how to pick the best 4×4 fence posts at the lumber yard. Avoid posts with excessive bark or knots, and check the end grain to avoid peeler cores. Ideally you are looking for posts with tightly spaced grain from the heartwood of the tree.
But what do you do when the available stock looks like the image above? Every single one of these posts appears to be a peeler core. In this situation you are better off trying a different location, but you may have to get creative. Because peeler cores come from plywood production they are usually 8 foot lengths.
If all the 8 foot posts are peeler cores, another option is to buy a 10 foot post and then cut the excess. The 10 foot posts are usually not that much more expensive than 8 footers. If you use this option, be sure to put the uncut end into the ground and use a quality preservative on the cut end.
Protecting Your Posts from Moisture
Wood posts typically fail right at ground level – the post above the ground is still strong and so is the wood further in the ground, but the section right at the ground line fails first. This ‘collar rot’ and is caused by moisture. To keep your fence standing for a long time the best thing you can do is keep anything that traps moisture away from your post.
We struggled with replacing posts that had broken off at ground level until we figured out a way to remove the concrete footing easily and without digging. Here’s how we slide the concrete out using water pressure. The Wood Post Puller patent was issued 8/28/2012 (US Patent 8,250,787) and we sold our own tools until 2017. Now we recommend the Corona RootIRRIGATOR (buy on Amazon) for its quality construction and excellent performance.
Keep the ground clear around the post and remove any mulch or vegetation. If you use concrete footings to set your posts, make sure the concrete is domed and tapered away from the post so it doesn’t hold water. One of the big problems with concrete is that the wood can swell and crack the concrete or the wood will shrink and pull away from the concrete. Both of these situations hold water against the post and accelerate rot.
Pro Tip: One of the best things to preserve your fence and extend the life of your posts is to do annual maintenance. Reapply a quality wood preservative (here is our favorite for good price on Amazon) to cover any damaged areas from weed eating and recoat the post at ground level.
How Much Does a Treated Post Weigh?
With so much water in the wood grain from the treatment process the weight of a wood post can vary a lot. A typical 4x4x8 treated wood post will weight around 38 pounds. Remember that tight grain structure and avoiding peeler cores are the most important factors – a good post will be heavy.
How Much Does a Treated Post Cost?
Cost vary by geographical location and where you purchase your lumber. The table below has typical prices for what you can expect at a big box store for #2 pressure treated lumber rated for ground contact.
|Nominal Post Dimensions||Length||Approximate Weight||Cost|
|4×4 in||8 ft||34~42 lbs||$8|
|4×4 in||10 ft||42~54 lbs||$12|
|4×4 in||12 ft||50~66 lbs||$15|
|4×4 in||16 ft||67~87 lbs||$20|
|6×6 in||8 ft||67~77 lbs||$23|
|6×6 in||10 ft||83~97 lbs||$27|
|6×6 in||12 ft||99~117 lbs||$37|
|6×6 in||16 ft||133~155 lbs||$46|
Remember that a 4×4 post is not actually 4 inches by 4 inches, each side will measure between 3.5 to 3.75 inches. Because pressure treated wood is sold very wet, the typical shrinkage from drying has not finished yet so pressure treated wood is always larger than kiln dried lumber. Length is not affected so an 8 ft post should measure 8 feet long.
When you are shopping for your fence posts you will probably find green pressure treated 8’ landscape timbers nearby and think to yourself “those timbers are a lot cheaper than these 4” x 4” pressure treated pine posts, I’ll just save some money and use the landscape timbers” – don’t do it! The landscape timbers may last for 1-3 years but will certainly be weaker and fail sooner than the proper pressure treated pine post.
Fence rails should also be pressure treated for the longevity of the fence, but the rails are not exposed to the same severe environment underground as the fence posts so AWPA grade UC3B is appropriate for unpainted fence rails. If you plan to paint your fence rails or apply an opaque stain then AWPA grade UC3A may also be used.
The choice of fence pickets is more of a personal preference based on the appearance that you want and if you plan to finish the fence with a paint or stain. Cedar pickets are the most common choice for their combination of pleasing appearance and natural insect resistance all for a reasonable price. White cedar is a better choice if you will apply a translucent or semi-opaque stain as the color will be more predictable than red cedar – although many of the common stain manufactures have color samples for each of their stains on the common wood types. Spruce or ‘pine’ pickets offer a more rustic appearance and are more commonly installed in 6inch widths.
Fasteners – Nails and Screws
Note the presence of copper in each of the pressure treatment methods – copper is necessary to provide the protection against decay and insects but it also has some negative effects. Copper will corrode standard fasteners much faster than regular wood – fasteners should be hot-dipped galvanized or stainless steel materials (meeting or exceeding the requirements for ASTM A 153 Class D standard for durability).
What Species of Wood are used in Pressure Treated Lumber
The three softwoods below are commonly interchanged because their structural properties are very similar. In fact, the entire category is abbreviated SPF for spruce-pine-fir and may contain any of the varieties intermixed.
Pine and Yellow Pine
Pine is one of the most common woods used for privacy fences. The wood is affordable, yet durable. Pine is often treated with a water repellant stain to prevent rot and to make the wood last longer in wet climates. Pine can also be treated with CCA, or chromated copper arsenate, to make the wood resistant to insect and bug infestations.
Pine comes in all levels of quality, at different price points. The best Pine boards have no knots. This means that every part of board is usable when constructing your privacyfence. While it comes at a higher cost, it can often be more economical, since you don’t have to discard any material during construction. Pine boards with a knot-free surface also allow for easy treating with stains and coatings.
Fir and Douglas Fir
Fir is also a common, affordable and durable material used for privacy fences. Fir woods tend to have a more unique look than Pine. Fir wood can be extremely strong, while also quite easy to cut. Like Pinewoods, Fir can be treated with water repellant stain to prevent rot and extend the life of your fence. Fir can also be treated with CCA, or chromated copper arsenate, to have a similar insect resistance as more expensive varieties of wood.
Spruce is most commonly used for prefabricated, stockade style picket fences. Like other standard quality woods, Spruce strikes a reasonable balance between affordability and durability. Spruce is not as prone to rot as Pine or Fir woods. To enhance the insect and bug resistance, Spruce can also be treated with CCA, or chromated copper arsenate.
Premium Wood Fence Posts
Whatever wood you choose, be sure to know how to treat and care for the wood to get the most out of your privacy fence. The right small touches can make any privacy fence look great for years. Here are three of the most popular woods with a higher level of quality that are also widely available:
Cedar is a solid wood with a middle-of-road price, high levels of rot resistance and unique coloring. Cedar is considered one of the most frequented fence materials because of its marble coloring and ability to absorb paint, stains, and other coatings very quickly and evenly. One of Cedar’s best qualities is that it contains natural oils to keep away insects. Keep in mind that Cedar needs to be treated with a clear stain to prevent turning grey over time.
While red cedar wood is slightly stronger than white cedar and also less prone to knotting, the real advantage is that white cedar has more oils so it is more resistant to insects and rot. White cedar fences outlast red cedar, sometimes by 10 years or more.
Cypress mostly comes from the southern part of America so, depending on your location, it can be expensive to procure. Cypress is naturally rot resistant and will give your privacy fence a much longer lifespan than standard woods. Also, Cypress contains a natural chemical called cypretine that works great to naturally repel most types of insects. Like Cedar, Cypress needs to be treated with a clear stain to prevent turning grey in color.
Once considered the gold standard for wood privacy fences, most people regard Redwood asthe most beautiful wood to choose for a privacy fence. Redwood is extremely long lasting and holds up well under all weather conditions. Redwood is extremely resistant to bugs and rot, without needing any treatment. A clear coat is all you need to keep this beautiful wood in prime condition. Unfortunately the Redwood you could purchase 30 years ago is no longer available and was replaced with much lower quality wood.
Even so Redwood still holds its reputation and carries a price premium. Redwood is one of the most expensive woods available and not economical for large projects for most homeowners. However, Redwood is recyclable, so there may be old projects that you can salvage to obtain it cheaper. You can also save money by using redwood for your panels, and other standard quality woods for your posts.
How do I choose a good 4x4 post? ›
Examine the stack of posts at the home center and reject the posts with end grain that looks like a bulls-eye. Choose the straightest posts you can find, with the least amount of center pith.What is the best way to remove fence post? ›
The trick to removing a fence post is to apply force upward, so that you're not fighting the strength of the earth on either side of the buried post. This can be done with a jack or machinery, or with a lever and some elbow grease. One of the best post-pulling techniques comes from Family Handyman reader Mike Barnes.How deep should the hole be for a 4x4 fence post? ›
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).
Pressure treated wood is sold with the lumber grades Premium, Select, Number 1, Number 2, and Number 3. The higher the grade, the fewer the defects—that is splits or knots. In general, you will want to choose Number 2 grade boards, or higher, for decks.What is a good reliable 4x4? ›
- Volvo XC40 - 93.69% The Volvo XC40 continues to hold a solid reputation for reliability. ...
- Kira Niro - 93.71% ...
- Toyota C-HR - 93.96% ...
- Kia e-Niro - 94.36% ...
- Kia Xceed - 95.56% ...
- Mazda CX-5 - 95.57% ...
- Hyundai Kona - 95.71%
If properly treated and installed, pine fence posts can last for 20–35 years; untreated pine posts might only last 3–7 years.What machine removes fence posts? ›
The Hi-Lift Jack PP-300 Post Popper is designed to remove metal T-posts, wooden fence posts, cement plugs or small stumps. The innovative design allows you to apply a tremendous amount of lifting force directly on the post, lifting it straight out of the ground.How do you pull a pole out of the ground? ›
If you can dig around the post with a regular shovel or spade, you can loosen the post's foundation. The trick is to dig out soil from one side of the fence. To get maximum leverage, you'll need to dig further than the base of the post. This will allow you to tip the post and extract it by lifting.How do you remove a 4x4 post from concrete? ›
One of the best methods for digging out fence posts by hand is to only remove the dirt around one “face” of the fence post. By digging slightly deeper than the base of the concrete, you can then tip the post into the hole and lift it out.Can you put dry concrete in a post hole? ›
Fast-setting concrete is ideal for setting posts because there's no mixing—you simply pour the dry concrete from the bag right into the hole, then add water.
How wide should a hole be for a 4x4 post? ›
The diameter of your post hole should be three times the diameter of your post. So, if you're planning on using a four-inch round or 4x4-inch square post, your post hole will need to be 12 inches in diameter. For a six-foot-high fence post, we would need a hole that's 36 inches deep and 12 inches in diameter.How long does quikrete take to set in a post hole? ›
QUIKRETE® Fast-Setting Concrete sets in 20 to 40 minutes. Wait 4 hours before applying heavy loads to the post, such as a basketball backboard. (If the temperature is below 72 degrees, additional time for curing will be required.)Is brown pressure treated wood better than green? ›
As mentioned, the only difference between Green and Brown timber is the Brown dye used during preservation - this does make Brown timber slightly more expensive to buy. So, when a product is referred to as 'Green timber' you'll know that it's been treated but left in its natural colour.What is the longest lasting pressure treated wood? ›
Pentachlorophenol-treated posts exhibited durability in excess of 60 years, whereas lumber specimens treated to standard ground-contact retentions had no failures after 39 or 45 years.What is the best quality pressure treated wood? ›
- Premium - Highest grade for ¾ radius edge decking.
- Select - The highest grade available, contains very few defects. ...
- Number 1- Will contain no splits larger than the width of the board. ...
- Standard - Mid-range grade for 5/4 decking.
- Land Rover Defender.
- Dacia Duster.
- Toyota Land Cruiser.
- Ford Ranger.
- Land Rover Discovery.
- Mercedes G-Class.
- SsangYong Rexton.
- Jeep Wrangler.
- Toyota RAV4. Although you'll struggle to find a Land Cruiser or Hilux at an affordable rate, Toyota's cheaper RAV4 can provide everything you need. ...
- Land Rover Freelander. ...
- Skoda Yeti. ...
- Suzuki Jimny. ...
- Nissan X-Trail. ...
- Dacia Duster. ...
- Volvo XC70. ...
- Ford Ranger.
The Toyota Land Cruiser has been one of the toughest and most reliable sport-utility vehicles for more than 60 years.Why put gravel under fence post? ›
DO Employ a Base Gravel Layer. If a fence post fails without any sign of a pest infestation, it's likely that the failure was caused by moisture that rotted the wood over time. To help slow such deterioration, add pea gravel or crushed stone to the bottom of the posthole.Should pressure treated posts be set in concrete? ›
With pressure-treated posts, the rot will be slow. We have three ways to solve the rotten post problem. First, the posts should be set on top of a bed of coarse gravel 3 to 6 inches deep, so the base of the post is in contact with the gravel. Concrete should be poured around the post - no concrete under the post.
How do you keep pressure treated posts from rotting? ›
Set in Gravel and Concrete
Fill the first three inches up with gravel so the end of the post doesn't come into contact with the dirt. Gravel allows water to drain quickly away from the post and into the soil. Be sure to place the post in the center of the hole. Finally, fill the entire hole up with cement to the top.
The first tip for working with pressure-treated lumber is to let it dry before using it. Other woods such as redwood and cedar are dry when you buy them. But lumber that has been treated has been injected with massive amounts of chemicals and water.Can I leave pressure treated wood in the rain? ›
While the chemicals in pressure treated lumber prevent rot and ward off insects, they don't prevent moisture from seeping into the wood. On a deck that's going to be directly exposed to rain, water can seep into the boards and cause them to swell.Why do 4x4 posts crack? ›
Pressure and moisture are the big crack culprits. New wood is wetter inside than many homeowners realize. Not only is there natural moisture, but lumber is often treated with chemicals to prevent rot. As the sun dries your new wood fence, it sucks out moisture, putting pressure on wood fibers.Do post pullers work? ›
There are many ways to remove a fence post but one of the easiest ways is to use a T post puller. It's fast, reliable, and requires little work. The 21-pound JackJaw fence puller pulls fence posts, string link stakes, and 3/4" form stakes in concrete applications.What tool do you use to remove wood posts? ›
The NW Quik Pull is the simplest and easiest way to pull out a fence post and the concrete plug attached to it with the least amount of effort. If you're looking for the best manual fence post puller on the market today, you've found it!How much force is needed to pull a fence post? ›
Removing and replacing a fence post is laborious and requires substantial effort. A vertical force of approximately three thousand five hundred pounds is required to remove a four inch metal post with twelve inches round and forty-eight inches deep concrete footing.How far out of the ground should be a fence post be? ›
Keep the height of your fence in mind when digging your post holes. As a general rule of thumb, you'll need to place at least 1/3 the height of the post in the ground. For example, a 6-foot tall fence will need at least 2 feet of post in the ground. Consider the frost line in your area.How much should a post go into the ground? ›
The general rule of thumb when setting a post is that the depth of the post's hole needs to be one-third to one-half of the actual above-ground height of the post. So, a six-foot-high finished post ideally needs to be buried three feet into the ground.How far should a pole go in the ground? ›
Poles are typically set into the ground: 10% of the overall height + 2 feet, except in questionable soil conditions. Example: Overall pole height: 30 feet, the pole should be buried: 3 feet + 2 feet = 5 feet below grade, and 25 feet above grade.
How do you replace a fence post without removing concrete? ›
The best way to replace a fence post without removing the concrete footing is by prying it out. You can do this with a long lever and fulcrum or a car jack. In either case, nail some wood to the post first to pry against and then get to work. Pry until the post releases from the concrete and comes all the way out.How do you put a pole in the ground without concrete? ›
Gravel: Filling the hole with gravel will help to support the fence post. This method is stronger than using dirt, but not as strong as using cement. Sand: Filling the hole with sand will help to support the fence post. Like gravel, this method is stronger than using dirt, but not as strong as using cement.How do you replace a rotted 4x4 fence post? ›
- Detach Fence From Old Post. Inside Attachment: Go to the rail side of the fence. ...
- Unscrew Fence From Old Post. ...
- Remove Old Fence Post. ...
- Clear Hole or Dig New Hole. ...
- Lay Gravel. ...
- Set New Post in Hole. ...
- Fill Hole With Dry Concrete. ...
- Add Water to Concrete.
Get a long length of something strong like 4x2 or steel box section. Fix it to the post with a meaty screw. Place a fulcrum as near to the post as possible and lever down on the other end of the shaft. The post should move.How do you break concrete off of a wooden post? ›
Break the concrete footing into two or more sections, using a cold chisel and steel mallet. Drive the tip of the chisel into the seam between the base of the post and top of the concrete until the concrete breaks. Repeat this on the opposite side of the post.How many 50 pound bags of concrete per fence post? ›
At least 2 bags per fence post, sometimes more depending on the size of the hole and the post.Can you pour quikrete in a hole then add water? ›
Whether you are building a new fence, setting a mailbox or anchoring a basketball goal or play set, QUIKRETE® Fast-Setting Concrete is the ideal product for the job. With Fast-Setting Concrete there is no mixing or tools required – You simply pour the dry mix right from the bag into the hole, then add water.What happens if you put too much water in concrete fence posts? ›
When a concrete mixture is too wet, it causes a greater amount of shrinkage during the drying process than is needed. As a result, the concrete has a great likelihood of cracking and for those cracks are likely to be a fairly good size.Is 2 feet deep enough for fence posts? ›
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).Should you cement fence posts? ›
Most use concrete to create leverage. The main reason is the post length of choice for fence companies is often a 4″ x 4″ x 8′. As a result, the fence post is only two feet in the ground on a six-foot in height wood fence. Hence the use of concrete.
How far apart should 4x4 fence posts be? ›
The standard spacing for fence posts is 8 to 25 feet apart, depending on the type of fence. A standard wood fence would require posts 8 feet apart, while a high-tensile wire could span 25 feet.How many bags of Quikrete do I need for a fence post hole? ›
Summary: How Many bags Of Concrete Per Fence Post? 1 – 4 bags of concrete per fence post are typically what's needed. This depends on the type of soil, fence design, height, post size and bag weight. In general the depth of the post's hole needs to be 1/3 to 1/2 of the above ground height of the post.How many 80lb bags of concrete per fence post? ›
For reference, a 40-pound bag of concrete typically yields about 0.3 cubic feet, a 50-pound bag yields 0.37 cubic feet, a 60-pound bag yields 0.45 cubic feet, and an 80-pound bag yields 0.6 feet. This means that in the example above, each post would require about eight 50-pound bags.How long will a treated 4x4 post last in the ground? ›
Slow the Wood Rot
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. By comparison, an untreated wood fence post may need replacing in as little as five years.
Step 3: Place and Secure Frame. Mix two 50lb bags of concrete with water in a mixing tub or 5-gallon bucket. Add concrete into the hole and around the 4” x 4”. Depending on your climate, let concrete set up for 24 - 48 hours.How much weight can 4 4x4 posts support? ›
How much weight will sustain a 4 rubber 4 post? Complete height of 9 feet is measured at about 5000 lbs with a perfect weight distribution on both 44 ends with the post in the vertical position.What is the best wood to use for posts in ground? ›
Pine is the most common and, when pressure treated, can last for up to 30 years. Other long-lasting types are Redwood and Sweetgum. Some tree species don't need to be treated and can last up to 25 years. Primary among them are Black Locust and Osage Orange.Should wood fence posts be set in concrete? ›
It doesn't matter if it is a do-it-yourself (DIY) project or a professional installation, wood fence or vinyl fence, your fence posts should be set in concrete. Without a properly set concrete footer, your fence posts will begin to sag until they eventually fail.How many bags of quikrete do I need for a 4x4 post? ›
1 – 4 bags of concrete per fence post are typically what's needed. This depends on the type of soil, fence design, height, post size and bag weight. In general the depth of the post's hole needs to be 1/3 to 1/2 of the above ground height of the post.How long does concrete take to set in a post hole? ›
How long does concrete take to set in a post hole? We would advise waiting at least four hours before any weight or pressure is applied to the posts or fence holes. For best results, you should wait at least 24 hours before you continue hole and fence construction.
How far can you span 4x4 post? ›
The maximum spacing of 4x4 deck posts should be 6 feet on center, while the maximum spacing of 6x6 deck posts should be 8 feet on center.Is a 4x4 post strong enough? ›
However, experienced contractors will tell you that a 4×4 post simply can't carry the heavy load that many porches require. Most professionals will encourage you to consider going with a 6×6 deck post form the outset of the project.Are 2 2x4 as strong as a 4x4? ›
2 2x4s glued together should be stronger than 1 4x4 because of the glue, but not necessarily stronger in the case of the OP's planks screwed together.What wood do farmers use for fence posts? ›
Permanent fences will require decay resistant fence posts. The most common wooden posts are pine pressure treated with CCA (chromated copper arsenate.) These posts have a greenish color, and they last longer and are harder than older treatments such as creosote and Penta (penta-chlorophenol.)How do you keep wooden fence posts from rotting in the ground? ›
Set in Gravel and Concrete
Fill the first three inches up with gravel so the end of the post doesn't come into contact with the dirt. Gravel allows water to drain quickly away from the post and into the soil. Be sure to place the post in the center of the hole. Finally, fill the entire hole up with cement to the top.
Placing a thick layer of loose gravel at the bottom of the post hole will allow groundwater to trickle through the rocks and down away from the base of the post. This will prevent the post from rotting by keeping it constantly dry. You can purchase gravel at a local hardware store or landscaping-supply business.