At first glance (and I really do mean a cross-eyed-peek-in-pitch-black), it appears that Concrete Piles and Push Piers are remarkably similar.
Both Concrete Piles and Push Piers are commonly utilized on a nationwide scale to repair foundation settlement.
Both systems are implemented under your home, both are hydraulically driven into the earth, and both claim to ensure maximum practical recovery.
Some people might be inclined to chalk it up to same principle, different tools.
However, we’re not talking two peas in a pod here. In fact, some comparisons just aren’t fair.
Id Est – would you rather vacation on the pristine sands of Fiji or visit Detroit? Would you rather win a million bucks on a scratch-it or undergo a root-canal surgery in a dirty basement sans Lidocaine?
The comparison is more nuanced than simply concrete vs steel or pipes vs blocks or shallow vs deep depth.
Push Piers lift, stabilize, and secure your home and prevent further settlement.
Concrete piles may lift your home initially, but often don’t go deep enough to provide any real, long-lasting support.
The primary reasons Push Piers outshine their crusty concrete cousin is because push piers penetrate deep into bedrock/load-bearing stratum (with verifiable PSI readings) and Push Piers utilize end-bearing support over friction or skin friction support.
Consider this article a back-to-basics 101 overview of both Push Piers and Concrete Piers. In this blog post, we cover:
- End-bearing Support vs Skin Friction
In short, we will briefly define the products, outline how they are used, discuss the importance of depth (penetrating the active zone) & PSI, discuss end-bearing support & skin friction, and finally compare dollars-to-doughnuts for cost.
So – let’s dive the heck right in (but be careful, Concrete Piles are definitely on the shallow end).
Concrete Pile Definition
A concrete pile is a reinforced concrete column that provides structural support. These either come:
- Precast (already created) and are then hydraulically driven into the soil
- Cast-in-situ (a hole is dug, a cylinder rebar cage is wedged in, and concrete is poured around this concrete pile already positioned)
Now, most of the time when you think of Concrete Piles, you envision those big, bad boys typically implemented for superstructures – bridges, skyscrapers, and your mother-in-law’s ego.
However, when it comes to concrete piles utilized in foundation repair, they are much smaller. They generally range from 12 inches wide to 12-18 inches tall.
Concrete Pile Utilization
The concrete piles are hydraulically pressed into the ground, typically with a bottle jack.
They are positioned underneath a home’s foundation and rely solely on compression/ skin friction for support (more on this fiasco later).
Remember, concrete piles are basically a defensive line: squat, chubby, not terribly aerodynamic.
It can prove incredibly difficult to get these fat boys past the active zone and lodged into competent load-bearing stratum.
Fun Terms with Brian: Active Zone
An active zone, as it’s referred to in the biz, is the soil generally 5-7 feet beneath your foundation. We call it active because it moves and is particularly sensitive to rain, frost, drought, and seismic activity.
Note – Because concrete piles don’t go deeper than the active zone, when the dirt moves, the piles move, when the pile’s move they angle/sheer off and provide little to no support for your home – so your house moves.
Remember, concrete piles rely solely on compression – meaning, they are not attached like push piers.
Concrete Pile Shish Kabob
Concrete Piles are often hybridized to make them work more similarly to push piers.
Push Piers fit together seamlessly, providing inherent support through this interlocking method that is just unachievable with concrete piles.
However, some contractors try to utilize the same strategy with crusty concrete piers.
For example, some piles are 6 inches to 8 inches wide, strung on a wire like a Concrete Pile Shish Kabob, and hydraulically driven into the earth (this cord is then pulled tight).
Shims are then fit between the top of the pier and the footing. The over-lifting process necessary to shimmy often leads to further foundation damage.
This further foundation damage in conjunction with the fact that there is no guide-sleeve for concrete pile installation (so these piles don’t go down straight), should be enough to scare off anyone seriously considering concrete piers.
Concrete Pile Depth and PSI
If you’re going to sink a good chunk of change into your home (and, trust me, we understand the fiscal bite), you better be damn well sure you’re getting what you pay for.
Unlike when you take out a $20,000 loan for that American-muscle Dodge Charger, there’s no purring motor to show off to your friends after a foundation repair. In fact, there’s not much to see.
We utilize gauges (a visual representation) during installation to calculate the load and monitor the loading capacity throughout the duration of the installation.
We require a baseline 2:1 factor of safety, but we often achieve a 4:1 or even a 5:1 factor. Meaning – the piers are holding up far less weight than they can actually hold.
To come up with the true loading value or capacity of the Push Pier, we would need to take the PSI and multiply it by the effective area of the ram/drive cylinder.
In short, PSI pressure is important, but do not let a foundation contractor sell you on PSI value alone – they are missing the rest of the equation: the effective area of the ram/drive cylinder.
So, if you don’t use a gauge, then how do you determine loading value? You can’t.
The problem with Concrete Piles is that not only do they not penetrate the active zone and/or retain enough friction to stabilize/lift/secure your home – they rarely utilize gauges.
In short, without a gauge, there is simply no way to monitor exactly how much pressure is being used.
Consequently, the construction crew never really knows when or if they’ve hit bedrock or competent load-bearing stratum.
Instead, construction crews drive concrete piles down until refusal and/or equipment failure.
Simple Math: resistance/refusal does not equal bedrock and/or load-bearing strata.
So, now that you know that concrete piles don’t penetrate the active zone or utilize PSI as a gauge for competent, load-bearing soil – you understand installing them is like crossing your fingers as the Titanic sinks.
All the good thoughts, vibes, and prayers won’t stop this ship from going down, baby.
Concrete Piles rely on skin friction – and, nah, it’s not frisky.
Skin friction is where the load is transferred through the shear stress that is generated along the interface of pile and soil. The pressure diffuses outward and often into soil that’s not secure.
Here at Dalinghaus Construction, we believe in the KISS Method – Keep It Simple Stupid.
So, simply put: skin friction is when the earth wraps up concrete piles in a bear hug.
This is a very tight grip; however, the problem is this bear moves (remember the active zone) and shakes like a drunk uncle embracing you at a family reunion.
Now, it is important to remember concrete piles rely on compression. They are not attached to your home’s foundation or footing.
So, when the earth decides to shake, shake, shake like an Etchy Sketchy those piles will slip out from underneath your foundation and cease to provide support.
Note – when it comes to bear hugs from the earth, it’s important to think in terms of collateral damage. Innately, concrete piles are not exactly indestructible.
I mean, they sure weren’t formed by the Dark Lord Sauron in the fiery belly of Mount Doom. They break, fracture, and chip on the regular.
Concrete Pile Cost
Foundation repair concrete piles typically cost between $800 to $1,200 here in Southern California and Arizona.
Granted, they come out a bit cheaper upfront than Push Piers or Helical Piers, but here’s the rub: Concrete Piles don’t last and will cost you more in the long run due to more repairs because you have to repair the repair.
Push Pier Definition
A Push Pier is a steel pipe that is hydraulically driven into competent, load-bearing soil and attached to a home’s footing via a remedial bracket.
Push Piers and their extensions are typically 30 inches (2.5 feet) of galvanized steel with a max capacity of 68 thousand pounds.
Note – Push Piers have reduced skin friction thanks to their sleek design and choke collars that provide some extra initial width. They can afford to be thinner because they rely on end-bearing load placement (definition coming up soon).
Push Piers have a brother Pier called the Helical Pier.
Push Pier Utilization
Push Piers have long been the industry standard for effective, long-lasting foundation repair.
I like to think of them as deep, steel roots that lodge down well past the active zone into load-bearing strata.
No matter how hard the drunk hug – these piers aren’t going anywhere.
Push piers are attached to a remedial bracket which is mounted to the manicured footing of your home’s foundation.
These piers go in every six feet around the perimeter of your home into 3×3 excavation holes that are dug below the footing.
These push piers interlock and are driven straight into the earth and kept straight via a guide sleeve.
Once the piers have reached bedrock and/or load competent soil, the home is lifted, and the holes are backfilled.
Note – Because Push Piers utilize the inherent weight of your home to hydraulically drive them into the earth, some homes are too light to do this successfully. These projects require helical piers.
Push Pier PSI and Depth
Unlike Concrete Piles, Push Pies utilize im-pier-ical evidence when it comes to pressure.
Push Piers are driven into the earth via a hydraulic RAM and the PSI pressure (pounds-per-square-inch) is meticulously recorded and logged via a gauge.
The industry refers to these documents as Pier Logs.
The foreman records exactly how deep the piers were driven and how many pounds-per-square-inch it took to reach the desired lift. On average, the goal is to hit 10,000 PSI for installation pressure.
This number ensures we have reached an appropriate depth, well past the active zone, and lodged securely into competent, load-bearing stratum.
There is no guesswork here or hocus-pocus. You can rely on our readings.
Push Pies do not rely on skin friction for support. Instead, Push Piers rely on end-bearing and carry their full load at their point and/or the toe of the pile.
Consequently, the pressure is not displaced to the soil encasing the pier, but rather to the soil directly underneath the pier.
So, back to our drunk uncle analogy – imagine your uncle is 5’3 and tries to pick you up at 6’6 and 300 pounds.
The bear hug will move and strain, but you will be secure because you are rooted well past the active zone – your uncles’ arms.
Push Pier Cost
The average general contracting cost per Push Pier in Southern California and Arizona ranges from $1,800 to $2000.
Dalinghaus Construction charges $2,000 for each push pier that we install, and we do not have a pier depth clause.
We also offer a push pier price of $1,750 per pier, but it does include a depth clause after 21 feet on installed material.
Push Piers are a moderately priced option, but a permanent fix that, in the end, will justify any money you sink into not sinking your home.
That’s why we here at Dalinghaus offer a lifetime warranty on all of our Push and Helical Piers.
Concrete Piles are Pier-posterous
In short, concrete piles just don’t go deep enough to penetrate the active zone and rely too much on compression for a skin friction pile.
Sure, they might last for a while, but when the drunk uncle shows up – expansive soils, rain, and/or seismic activity – it’s over.
Push Piers go deep, reach 10,000 PSI, lodge into load-bearing stratum, and utilize their end-bearing advantage to stay secure even when the earth shake, shake, shakes.
But, this is only the beginning of the wonderful world of Piers. You should check out our blog post about Push Piers vs Helical Piers – a more even matchup.
If you live in sunny SoCal or in the Grand Canyon State, click on the link below to book a FREE foundation inspection and see if Push Piers or Helical Piers are right for you…