Bell-Bottom vs. Pressed Pile Foundation Repair Methods: What’s the Difference?

It has recently come to your attention that foundation repair is needed on your home. You might be working on getting estimates or haven’t started yet. You might be thinking that “foundation repair is foundation repair” and “it’s all the same, you just gotta find someone to do it” for you. Wellllllllll, I hate to break it to you but it’s not all the same.

There’s more than one way to skin a cat. Have you ever heard this graphically hideous and gruesome saying before? Well, I didn’t either until I met my “born in the south” husband but that’s another story . . . 

Anyway, the saying translated into non-hayseed means “there’s more than one way to do things.” There are some different methods available in the foundation repair world. Don’t worry, none of the methods involve cats.

Slab foundations can be repaired using a few methods. The two most typical are the pressed pile system and the drilled pier with an underream system. In less *engineery* words, the second one is commonly called a bell-bottom pier system.

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At Anchor Foundation Repair, we have repaired over 4,000 foundations in the Bryan-College Station and the greater Brazos Valley area over the past 35 years. Not only do we offer foundation repair solutions for our community, but we also want to be a resource for all-things-foundation-related as a service to you.

We repair foundations only using the bell-bottom pier method and do not use the pressed pile system. Although we do only provide one of these services, our commitment to education and knowledge means that we want to present this information in the most unbiased way possible so that you can make a sound decision for your home. 

Even though we do have a preference in methods, we recognize that each home and homeowner has unique needs and that there is no perfect solution for all scenarios. We will never hesitate to point you in the direction of another contractor if that is what is best for you.

In this article, we will compare and contrast in simple non-industry language how each of these methods works and outline their pros and cons. We will also present some situations or homeowner types that each method might be best suited for. 

By the end of this delightful foundation repair narrative, you should be able to identify a method that speaks to your needs and will serve you best. 

What is the same about both methods?

holes around a home
Support locations

Both the pressed pile and the bell-bottom pier methods have some basic similarities. Both methods use a vertical support structure in the ground to lift, level, and hold the home in place. Engineers would call this “underpinning” and either piles or piers are used to provide this vertical support under the home. 

Piers in foundation repair are not the kind of pier that you fish off of near a body of water. Piles are not the kind made out of dirty laundry waiting to be washed. Instead, think of a beach house that is up on “stilts” raised above the ground to keep it away from water that might come ashore. 

Now picture pushing that home down, those stilts being sunken underground, and the home resting on top of them and the soil. Each pier or pile invisibly helps to support the weight of the home and keep it level.

Generally, the number of piers or piles needed to support any given foundation repair scenario will be the same for each method. So both methods will use a vertical underpinning system that goes into the ground under the home and will use the same number of piers or piles to complete the repair. 

What’s different about the methods is how the “stilt” is made, installed, and how it works to keep your home stable. We will go over these differences in the next section.

Pressed Pile Method Overview

Luckily, once I explain this method to you, the name will make perfect sense. The pressed pile construction sounds exactly like what it is so it will be easy to remember.

Construction of Pressed Piles

children's play beads
Those blue beads look a lot like pressed pile cylinders.

Pressed piles are made out of a bunch of concrete cylinders piled on top of each other and pushed underground. Each cylinder is 6” in diameter and 12” tall. Picture the wooden beads you strung into a necklace as a child.

The cylinders are a standard construction item made in advance that is brought to your home for use. They are topped with a pile cap, which is another piece of pre-made concrete shaped with a wider surface area on top.

Installation of Pressed Pile System

Workers push the cylinders into the ground one by one using a hydraulic jack. They sometimes use the aid of hydropower to drive them further into the earth. The repair crew would continue pressing more and more cylinders stacked on top of each other in a pile until they can’t anymore. Is the name starting to make sense now?

These pressed piles of concrete cylinders will be placed at each needed support location and the pile cap placed on top, then the home is raised using jacks at each location and held in place with shims. This is a very basic description of the installation, for more specific and riveting details on this process check back with us later when we have one written up.

inserting a battery
The spring is the soil pushing up and creating tension.

How Pressed Piles Work in the Ground

The pressed piles support the home through tension, kind of like a battery held into place with a spring on one end. In this case, the “spring” is the uplifting soil below the pier pushing up against the weight of the house.

Pros of the Pressed Pile System

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The biggest benefits of the pressed pile method are lower cost and quicker installation time. It is understandable that some homeowners want or need the least expensive repair method possible. It is also reasonable to sometimes want things done as quickly as possible, and pressed piles might take just a couple of days to install. 

If low cost or quick turnaround are your highest priorities, then the pressed pile pier method might be the best choice for you.

Cons of the Pressed Pile System

The downside to choosing pressed piles is that they are not as long-lasting for a couple of reasons outlined below. 

Moisture level on installation day can be a factor

The pressed pile method depends upon the weight of the home, combined with the moisture content of the soil on installation day, to continue working. The moisture level of the soil at the time of installation impacts the effectiveness since the moisture content of the soil pushing against the weight of the home is what creates the tension. 

If the ground becomes dryer after installation, the tension weakens and the home will need to shift to maintain the pressure or fall out of a position of tension. 

If the ground becomes wetter after installation, then tension increases and the piles may push up, causing the home to raise higher at the support locations and come out of level.

The pressed pile pier repair job on the same home may go completely different and use a different number of cylinders depending on the climate/moisture content of the soil at the time of installation.

For example, a lighter home built in the 1960s being repaired on a dry summer day will not press in the pile of cylinders very deep. But a new two-story stone house built in 2003 being repaired on a wet, winter day will find the pile of cylinders pressing more deeply into the ground and more cylinders being used.

Now imagine that the 1960s home is being repaired on a wet, winter day and the stone home is being repaired in the middle of the summer.

No assurance that the pile was installed vertical

Another con that can occur during installation: the pressing down of the cylinders can be knocked off course by a large rock, root, or tougher soil and veer from vertical. 

There is no way for the installer to know if this has happened because they are pressing the pile into the ground through pressure but there is not a continuous path or hole already dug that the cylinders follow.

If the pile of cylinders is not vertical, and also not connected to one another, the stability and longevity of the repair can come into question. The pile also may not go deep enough to ensure long-term carrying capacity.

Live load at installation time can be a factor

Another drawback, although minor, is that all the furniture and all your stuff inside the home, (also called the live load) at the time of installation can be a factor in how long this method lasts. If the weight changes by adding or taking away items from the home, the tension changes, and effectiveness can be compromised.

What situations or homeowners is the pressed pile method best suited for?

The pressed pile system can be beneficial for certain types of situations and homeowners. Here is the shortlist of times when this method might work best for you.

  • A homeowner that is selling soon and is not interested in longevity.
  • An investor looking for a quick turnaround time.
  • A homeowner with limited funds who wants the least cost to complete the repair.
  • An investor who is trying to keep a remodel job under a certain budget.
  • Anyone who doesn’t want the repair crew to be on site for a long time.

Bell-Bottom Pier Method Overview

Construction of Bell-Bottom Piers

Bell-bottom piers are hand-made on site. A hole is dug and a straight shaft is further drilled out into the ground. At the bottom of the shaft, a bell shape is created by a spinning tool that cuts into the earth, making a wider base for the pier. 

girl in bell bottoms
That’s not your mom, but those sure are some bell bottoms . . .

It makes sense that it is called a bell-bottom system because it really is very much like a pair of bell-bottom pants, straight down the legs and the bottom flares out at the end. The name is very fitting, kinda like those bell-bottoms your mom used to wear.

*Sigh* I have been told by my boss that bell-bottom piers were invented before bell-bottom pants but I want to pretend like it was the other way around for fun. I mean, actual bells were invented first really, and they are both likely named after that but I’m no historian . . . 

Steel rebar is inserted into the length of the shaft for strength. Next, concrete is hand poured on location into each pre-drilled hole that is between 10 to 12 feet in depth and then topped off with a steel-reinforced concrete cap. 

After the piers are poured, a waiting period (about 7-10 days) will go by to allow the fresh concrete to cure as much as possible for strength.

Installation of Bell-Bottom Pier System

The bell-bottom pier construction and installation happen at the same time since everything takes place on-site. Since all piers are made by hand, it takes more skill and experience to construct and install this system.

How Bell-Bottom Piers Work in the Ground

The bell on a bell-bottom pier works to resist the uplift of expansive soils and is not dependent upon the normal moisture level of the soil to work properly. The bell shape grips and pulls down with an “anchor effect” that holds the pier in position under our normal changing moisture and climate conditions.

This anchoring effect keeps the pier from pushing up on the home during wet seasons and keeps the pier from sinking down under drier conditions. Now the name Anchor Foundation Repair makes a little more sense too, huh? *winkie face*

Cons of the Bell-Bottom Pier System

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Just like any repair method, there are pros and cons in choosing the bell-bottom pier system. Because the piers are built individually on-site, the process takes longer and must include the concrete curing time.

The whole job takes longer because there are more steps in the construction of the piers with first digging, drilling the shaft, and then pouring the concrete by hand. This process takes more skill from the repair team due to the need for know-how about each step from digging, to operating a drill and the Beller, to pouring and finishing the concrete.

Cost: this could be con or it could be a pro

With more time and skill required for the job, also comes an increased price tag. A contractor using the bell-bottom pier method will likely have higher prices than a contractor that uses the pressed pile system. This may or may not be a bad thing, ever hear the saying “you get what you pay for?” You will have to decide if a higher price is a pro or con for yourself.

Pros of the Bell Bottom Pier System

The main advantage of the bell-bottom pier system is that it results in longer-lasting stability to the home. It can be confirmed that the pier was installed straight because they drilled the hole on-site, no chance that things went off course. 

pressed pile vs bell bottom pier diagram

It has been verified by an independent professional engineering team that this system resists uplift and settling in a way that pressed piles cannot due to the wide bell-bottom base. The system also does not depend upon the weight of the home resting on top of it to create the tension needed for effectiveness.

The effectiveness of this method also does not depend on the moisture content of the soil at the time of installation. Piers will be constructed and installed the same way no matter what the climate is like at the time or the live load weight at install time.

What situations or homeowners is the bell-bottom pier method best suited for?

  • A homeowner that loves their home and plans to stay in it for the duration.
  • A homeowner that wants to pass their home down to their children someday and doesn’t want them to have to worry about this repair later.
  • A homeowner that loves their home and is planning a fabulous remodel someday.
  • A homeowner that had made many memories in their home and wants the best care and maintenance for it.
  • A lightweight home that does not have enough mass to make pressed piles function properly. This would be true of small, older homes.

Choosing the foundation repair method that is best for your home.

All homeowners have different goals and needs while living in their home and the choice is ultimately yours when it comes to selecting a foundation repair method. 

I like to think of bell-bottom piers as personally designed clothing made just for you. Custom-fit, carefully made, long-lasting, and requires some experience and skill to get it right.

Pressed pile foundation repairs are more like clothing you buy at Target. Nice, gets the job done for a few seasons, may or may not fit perfectly because it was mass-produced in some ways. And how long it lasts might depend on what kind of day it was when it was made.

Is one method sounding more like your style? There is no wrong answer most of the time because Target clothing is great for some things, and bell-bottoms will always come back in style again eventually!

Foundation repair companies in our area specialize in different methods. We live in a smaller community and don’t have a great number of choices in each repair method type. So really when you are choosing a foundation repair contractor around here, you are also choosing a specific repair method. 

Anchor Foundation Repair chooses to use the bell-bottom pier system because we believe it to be the best method for all the pros listed above and have been perfecting the method for 35+ years. 

pressed pile vs bell bottom pier comparison image

We like that the method has the following qualities: guaranteed depth, confirmation that the pier is straight, a bell-bottom that best resists uplift and settling, not dependent upon climate conditions at the time of installation. 

We are so confident in this method that we also offer a lifetime warranty on our workmanship.

Anchor is best for homeowners who want to take the time to get the highest quality repair and the longest-lasting results so that you never have to worry about your foundation again.

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We realize that even after reading this article, you still might want to talk to someone about this decision. Anchor Foundation Repair can begin with a FREE phone estimate and later conduct an In-Home Assessment to help you decide. Contact us today for an honest and fair evaluation of your foundation issues.