Pressed Concrete Piers

Concrete piers are made up segments(concrete cylinders) that are pressed into the soil beneath the foundation each on the top of the previous, forming a continuous column or "Pier" of concrete cylinders.

Many concrete piers are manufactured with a 5/8 inch hole running through the center of the pier so that it can be threaded onto rebar, cable, or other materials that are stiff enough to add tensile strength along the length of the pier.

Pressing

Pressing is accomplished using the weight of the foundation and a hydraulic ram to force each segment into the soil directly under the foundation one on top of the previous until they cannot be pressed any deeper.

Installation

Installation begins by digging holes at regular intervals along the affected areas of the foundation. If a pier is necessary in an area that is covered by concrete such as a sidewalk or driveway, a hole must also be cut through the concrete in order to allow access to the foundation below. These holes that are cut through concrete must be filled after the piers are installed. It is usually the responsibility of the contractor to fill them with a poured concrete patch. It should be noted that it is nearly impossible to match the color of existing concrete with a patch. You should be prepared to live with this probability or plan on using some sort of surface coating to hide the patch.

The process of pressing cylinders continues until the piers reach bedrock or until the friction between the soil and the surface of the concrete cylinders becomes so great that the weight of the foundation is no longer sufficient to press them deeper. This is commonly referred to as the “Point of Absolute Refusal.”

After all of the cylinders have been pressed to the point of absolute refusal, hydraulic jacks are used to raise the foundation in multiple locations and a concrete cap and steel shims are placed between the top of the last cylinder and the foundation. All of the cylinders stacked one atop the previous are what constitutes a pier.

Once all of the parts are in place the jacks are then slowly released allowing the weight of the foundation to rest on multiple piers simultaneously, insuring that the weight carried by each pier is only a fraction of the weight that was used to press it into place. This is what makes the concrete pier applicable to many different situations.

Pressed concrete piers are probably the most versatile of all pier types. That is why it is the most popular and commonly used method of foundation repair. Use of pressed concrete piers probably accounts for more home foundation repairs than all of the other foundation repair methods combined. It is effective in most scenarios and is the only solution in areas where there is no bedrock or soil dense enough for other methods. It also usually costs less than other repair methods.

There are however, times when other repair methods may be more desirable. Those methods are covered in other articles on this site. Lets take a look at the advantages and disadvantages of pressed concrete piers.

Advantages

• Relatively quick to install
• If installed correctly, extremely reliable
• Is installed directly beneath the foundation
• Cost effective

Disadvantages

• Installation can be messy
• Plants may need to be removed but can usually be replaced

I like pressed concrete piers a lot and I recommend them a lot because of their versatility, dependability, durability and because they are one of the least expensive methods available.