The way construction crews build decks is sometimes outdated and troublesome. These convenient yet short-lived practices are the reason many decks see structural failure a few years after construction. Depending on the kind of deck you have, these kinds of structural failures can put you and your loved ones in serious risk of injury, since many decks are built a few feet above the ground.
The root cause of deck settling lies in the kind of pier or block that is used for the deck and how it interacts with the soil around it. Traditionally, concrete piers are used as supports. They come in assorted styles and sizes that serve different purposes depending on the size of the deck. However, no matter what kind of concrete pier you have, the deck will settle with time. This is because concrete pillars have too many structural flaws to combat soil displacement and the freeze-thaw cycle.
Helical deck piers are rods made of solid, galvanized steel. The end of the rod has helix blades that are welded to the shaft. What makes helical deck piers so great at supporting decks is their slender design, the material they are made of, and their ability to be driven deeply into the ground for maximum load-bearing capacity.
In Chattanooga, Tennessee, and surrounding areas, our AFS helical deck piers have many advantages that save you time and money. Among these are:
- Long-term deck support
- Anti-rust galvanized steel
- Does not rely on clear weather conditions for installation
- Small machinery allows for installation in tricky spots
- High load-bearing capacity
- Not affected by soil displacement
- Deck can be used immediately after installation
Helical Deck Piers vs. Concrete Deck Piers
Concrete piers are meant to be poured deep underground below the frost line so that the footing is not affected by the freeze-thaw effect. The freeze-thaw effect refers to the cycle water goes through as it freezes and thaws when the temperature gets low. The frost line indicates the depth at which liquid can freeze. At a certain point past that zone, the water would be too deep to be affected by the freezing temperatures above.
The reason you don’t want your deck piers to be affected by the freeze-thaw effect is because water expands when it freezes. Any water that saturates the soil within and above the frost line will freeze and expand by about nine percent. The expanding ice displaces the soil and leaves gaps, allowing water to flow through the soil and displace it further. If a concrete pier is placed within this area, it will mean that as the soil loosens up and becomes unstable, the pier will begin to settle against the shifting soil.
This is why concrete piers are built below the frost line. The reason there is failure is because a part of the concrete pier is still affected by the freeze-thaw effect, even if the footing is not. Over the years, the part of the concrete pier that is above the frost line becomes debilitated as the ice creates micro-tears. These tears weaken the tensile strength of the concrete, making it difficult for the piers to hold up the tremendous weight of the deck and whatever furniture is on it. That part of the pier becomes too weak to support the deck, and that is where the structural failure begins.
Because helical deck piers are made of galvanized steel (meaning they have a protective zinc coating), the rods do not erode or get affected by the freeze-thaw effect. Helical piers don’t have this problem, which is one of the reasons they are a long-term solution for deck settling.
How Helical Deck Piers Provide Decks With Superior Support
The soil on your property has multiple layers. The topsoil, which is the layer at the very top that you can see, is the softest layer. It is the most susceptible to soil displacement because it is exposed to the elements. Part of the reason the topsoil is so soft is that it has the highest concentration of organic matter and microorganisms of any soil layer.
The farther down you go, the less organic material you find. The deepest layers are known as load-bearing soils because they are tough and dense enough to withstand substantial amounts of pressure. They don’t shift easily and aren’t exposed to rain, snow, ice, wind, and other erosive elements, making them the most stable soil layers on your property.
Concrete deck piers are supposed to be built deep enough to reach load-bearing soils. This way, they rest upon soil that is able to hold up the heavy deck. However, concrete piers are not capable of reaching the same soil depths as helical piers.
Concrete piers cannot be made too long and thin. The longer and thinner they are, the less tensile strength it has and the less weight it is able to support. Therefore, concrete deck piers are typically short. You might think that making them longer and thicker could work, but then the piers run into another problem.
Concrete piers that are too large are susceptible to skin friction. Skin friction is when the soil that surrounds a deck pier causes negative pressure on the pier. This negative pressure causes the concrete pier to lose its load-bearing capacity and makes it unreliable for support. Concrete that has been mixed incorrectly or doesn’t have the necessary psi will crumble under the weight of the deck as well as the downward pressure caused by the skin friction.
This negative pressure is most likely to occur in softer clay soils because of how compressible they are. Nashville and Knoxville, Tennessee, as well as Huntsville, Alabama, have incredibly soft soils. Deck piers in these cities are constantly experiencing structural failure because the concrete deck piers aren’t strong enough to withstand all the pressure.
Helical deck piers don’t have this problem at all and can be driven deeper into the ground for maximum support from the sturdiest of soils. The surface area of helical piers is a lot smaller than concrete piers. Because of their streamlined design, they don’t compress the soil or suffer from any skin friction, so they never break and can withstand more pressure than concrete. Because you don’t have to worry about how much weight the helical piers can support, you have the freedom to decorate the deck however you please. You can turn your deck into a sunroom, add some shade, or move in more furniture.
Helical Deck Piers vs. Deck Blocks
Concrete deck piers aren’t the only supports used for decks. Low-level decks that don’t need to be supported by multiple, long posts are typically supported by deck blocks made of concrete. They are precast blocks that have slots where the supports posts are secured in.
The problem with deck blocks is that they are prone to settling. How the deck blocks settle against the soil depends on the kind of soil it rests upon. Places in Tennessee and Alabama, like Knoxville, Nashville, and Huntsville, are regions with clay soils. Clay soils swell up when exposed to water and shrink when all that moisture dries up. This constant shrinking and swelling displaces the soil until there are gaps and it is no longer as dense as it was before.
Other areas of Alabama, like Mobile and Birmingham, have sandy soil. Sandy soils drain water well and don’t expand when saturated with water. You would think this means that no settling is possible on sandy soils, but these kinds of soils get displaced very easily. The particles are bigger and they don’t compress well, making the soil loose and grainy. Sandy soils wash away little by little every time there’s rain, so soil in rainy states like Alabama see a lot of erosion.
Even if you replace the soil with gravel for soil erosion control, the deck blocks can still experience structural deterioration after only a few years of use. Plus, the gravel can shift around slightly when the loose soil that surrounds it shifts about as well, especially if the grains are small.
When a deck block no longer has a solid layer of soil to rest on, it sinks and settles against the uneven soil. With helical deck piers, there is no settling. This is because the piers rely on the load-bearing soil deep underground to support the deck. No matter how much the topsoil washes away or gets displaced, the deck will remain even and stable.
How Helical Deck Piers Are Installed
Besides their effectiveness, helical deck piers are preferred by many because of how easy they are to install. Here’s how it works:
Contractors determine where the helical piers need to be installed after careful consideration. Depending on the existing deck support system you already have in place, these will need to be removed or left in place.
No intrusive excavation is required for the installation of helical deck piers. They are simply driven into the ground by hydraulic machinery until they reach the right soil depths. Each pier can be installed as quickly as two minutes, so the entire job can be done in the span of a few hours. The machinery needed to install the helical piers themselves are small, so they can fit in difficult-to-reach areas with ease.
A base and a bracket are placed on each helical pier. These brackets can support standard 4×4 or 6×6 wooden deck posts. The posts are secured to the brackets, and the job is done. With poured concrete piers, you would need to wait for a few days for the concrete to cure before placing any weight on it. After a helical deck pier installation, not only can you use the deck as you normally would, but you can also begin any kind of remodeling right away.
How Can I Get Helical Piers for My Deck?
Sometimes, helical piers can be found in hardware stores, which may give you the idea to repair the deck yourself. However, not only are these commercial piers low-quality and less functional, it also takes an expert to be able to install any helical pier properly.
For a settling deck, you would need to know where each pier should be installed so they properly support the structure. Not only that, but you would also need to know how to operate the machinery to drive the piers through the ground, how to load-test the pier, and determine its bearing capacity. Depending on the kind of soil you have, you might also need helical piers with extra helixes, which is something you would only be able to determine if you are a professional.
Helical Deck Piers
FAQ's
Concrete deck piers and deck blocks are nothing but trouble. You may get a few good years out of them, but you eventually begin to see deck failure. Without proper support that is able to bear the weight of the deck evenly and consistently, you’ll be shelling out money for unnecessary repairs multiple times. This begs the question: If concrete supports are so bad, why do contractors still recommend and use them for deck construction?
Cost
Since the development of Portland cement in the eighteenth century, concrete has been one of the most used materials in construction. It is made of materials that are easy to acquire, so concrete structures are cheap to build. When building a deck, many construction crews try to give homeowners the lowest quote possible so they can get hired. Even if they know that concrete supports are not ideal, they go with it anyway because it’s cost-effective in the short term.
In the long term, however, concrete support systems do not come cheap. They will eventually fail and the deck will become uneven. However, many contractors are not interested in future-proofing structures. Most times, if they are built up to code and are stable at the time of construction, they will not put any effort into providing the deck with a better support system.
Tradition and Resources
Because engineers have relied on concrete structures for so long, decades of techniques and solutions are still passed down. Even though the methods are outdated, many contractors faithfully use the building techniques that involve concrete support systems. Many refuse to adapt to new methods because they believe that the old way is the best way. This failure to adapt is what causes decks to be built with supports that eventually deteriorate.
Installing lasting helical deck piers requires expert knowledge and special tools. Sometimes, contractors simply have not been trained on how to install them or don’t have the necessary tools to complete such a job. Instead of spending the resources to train their crew on how to use the best materials in the industry, many companies continue to rely on homeowners’ lack of knowledge in order to make decks with outdated systems.
Helical deck piers aren’t only useful for newly constructed decks. Even if you have an existing deck, they can be used to repair any settling or structural issue that has to do with the way the structure is supported. If your deck is experiencing structural problems but you aren’t sure if the actual support system is the cause, take a moment to familiarize yourself with the problem signs.
Obvious Problem Signs
The most obvious sign of settling would be an uneven deck. As the concrete support begins to deteriorate or settle, a portion of the deck will begin to tilt sideways. This is most obvious in decks that are a few feet above ground. For ground-level decks, it takes a significant amount of settling in order to notice the difference, but any kind of unevenness should be investigated, even if it isn’t severe.
As the deck begins to sink downward, the flooring on the structure will also be affected, so a sagging deck floor is another clear sign. If you have an attached deck, take a look at the deck ledger board, which is the wooden board that is used to attach the deck to the house. When settling, the deck will often begin to detach itself from the house, so any kind of damage to the board indicates settling even if the detachment isn’t significant.
Less Obvious Problem Signs
Some of the less obvious signs for deck settling require you to look at the smaller details in the materials that make up the deck. These smaller details begin to appear even before the settling becomes noticeable, so taking a moment to inspect things will allow you to act long before the deck begins to see severe damage.
The handrail on the deck will begin to warp as the structure sinks, and it might even damage the wood as the pressure causes it to lift from its bolts. If your deck has a cover that is supported by columns, take a look at them, and try to see signs of damage. As the columns also experience damage as the deck settles. You can even use a level ruler to determine if it’s slanting to the side. You can also look at the deck’s wooden support posts for any bowing or breaking.
Having a settling deck is extremely dangerous, especially if it’s a few feet above ground. Settling is caused by soil erosion, and it is especially important to make sure your deck is structurally sound when first constructed.
Helical Deck Piers
Deck settling is something that cannot be prevented completely. Soil displacement and erosion can happen due to rain, wind, and freeze-thaw. In places like Birmingham, Alabama, which is at the heart of a region where tornadoes are frequent, it’s hard to control how the weather will affect the soil.
What you can do is install helical deck piers. Even if your deck isn’t settling, if you want to truly make sure your deck will never settle, helical deck piers are the way to go. No matter the conditions of the topsoil on your property, helical piers will make sure your deck is always supported.
Preventative Measures
Even though soil erosion is not something that can always be controlled, there are things you can do to mitigate the damage caused by erosive elements. Every few years, talk to a landscaping expert to inspect your yard and make sure that it has a positive grade. A yard with a positive grade will drain any rainfall away from the property instead of toward it.
You can also add some skirting around your deck. Deck skirts are panels that are fitted to the bottom of the deck so that the underside is covered up. Not only do deck skirts prevent animals from making a home under your deck, but they also protect the posts and soil around the pier from extreme weather.
Get In Touch With AFS for Helical Deck Installation
If your deck is experiencing structural problems and you’re interested in helical deck piers, we can help. Since 2000, AFS has been proud to service multiple areas in Tennessee like Nashville, Chattanooga, and Knoxville. We also operate in areas in Alabama like Birmingham, Huntsville, and Mobile. We have established a reputation for high-quality service and innovative solutions in the areas we service, so you can expect expert installations from us. We offer free inspections, so don’t hesitate to give us a call so we can send a qualified field expert to inspect your deck. Use our online contact form or simply give us a call, and we’ll have your deck feeling stable and secure in no time at all.
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