Whether you're building a fence, setting a mailbox or even a basketball goal, the best way to ensure your posts will stay sturdy and true for years is to set them in concrete.
The best recommendation for setting fence posts of any kind is to always secure all metal fenceline poles in cement, plus all wooden corner and gate posts as a minimum. Doing so creates a footer that prevents the post from rising out of the ground or leaning for any reason.
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.
The answer -— as it often does in fencing construction — depends. As a general rule, Fencing Direct recommends at least a 24-inch footing depth for a 4-foot fence, plus an extra 3 inches for every foot of height (for example, 27 inches for a 5-foot 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).
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.
With concrete holding the moisture against the wood, wood has no chance and will eventually lose the battle. Now you don't have to lose all hope because it's for certain that the concrete around the post will crack, therefore making it easy to pull out when it starts to rot. Even worse, the concrete cracks early.
Once you've dug your hole, place about 6 inches of aggregate in the bottom of the posthole to allow for drainage. This will minimize the amount of water that comes into contact with your cedar fence post. Pro Tip: The bottom of the post should extend a few inches into the aggregate as shown.
Postsaver® is the number one choice for preventing fence post rot because it will literally block rot. It is a heat-shrinkable outer sleeve that fits over the base of the fence post. The sleeve has a thermoplastic bituminous interior liner, which seals to the wood.
But when it comes to the basement, you may be wondering if it's possible to install hardwood flooring directly on top of the concrete. The short answer is yes; but be sure to talk to the experts before making a final decision.
While cedar's tight grain, resistance to rot, and lack of knots make for optimal fence material – it is less durable against soil than pressure treated pine (in posts). For this reason, it may be a good idea to use pressure treated pine for the posts and cedar for the rest of the fence.
With just a minimal level of maintenance, concrete fence posts can last for around 25 years.
The 'quick' answer is that the finished, or good side of the fence faces the outside of your property, visible to neighbors and the outside world. That being said, the fence posts (or poles), rails, and other hardware are installed on the inside of the fence line and face you.
Adding a 6" gravel base under each post and finishing the concrete base so that it slopes away from the posts are popular methods for protecting posts against rot from moisture contact.
While treated timber posts can last from anywhere between 10-15 years, untreated timber may need replacing in under 5 years.
Use pressure treated wood in any situation where there's direct contact between the wood and anything that could supply moisture. This means posts in contact or buried underground obviously, but it also includes any lumber touching concrete or masonry since it's porous and wicks water like a sponge.
Long Exposure to Moisture
The rot of fences usually happens with prolonged exposure to moisture. The most common area this happens is near or in the ground. Soil tends to give fence posts prolonged exposure to water.
Then comes the rain, or the irrigation system. That water finds the gap. The bad stuff seeps downward right into the “Hot Zone”. Mix in some oxygen, the moisture from below, the fact that concrete holds a constant temperature and moisture, and those wood posts are going to prematurely rot.
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.
Complete calculation:
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.
Most fence posts require anywhere from one to 10 bags of concrete. Actual concrete amounts vary depending on post hole diameter and depth. Account for frost lines and gravel when doing calculations.
Screws should never be used when installing a wood fence. While research shown that nails are better for the installation of a wood fence, using the right type of nail is paramount. The list of nails available at your local hardware store is endless, and each nail is designed for a specific purpose.