Concrete piers are cost effective reliable, and easy to install, which make them the most commonly used pier for foundation repair. Their technical name is “pressed concrete piers”.
Pressed concrete piers are installed by digging a 2’x2’ hole under the edge of your foundation; a hydraulic press then pushes the 6”x12” cylinder into the ground. The cylinders are pushed to an average of 45,000 lbs pounds of force to their "point of refusal."
The piers are capped off and “shimmed” to an exact height using ¼” steel plates. In soils prone to shifting - side-to-side movement rather than up and down movement - a steel cable can be threaded through the cylinders to lock them into place.
One of the oldest methods of foundation repair, also referred to as drilled concrete piers, is still the preferred method of some engineers. The installation system is more invasive than the pressed pier system, since an auger is needed to drill an 8”-12” diameter hole 10’-15’ feet deep. Either a hand-held device or one mounted on a bobcat or similar vehicle could be used.
Once the hole is dug, rebar is placed inside and filled with 3,500psi concrete mixture. The hole must be left uncovered for 7-10 days for the concrete to sufficiently cure before your structure can be lifted.
Because the drilled pier does not rely on the weight of the structure to install it, the drilled pier is the most versatile pier, being used on both slab foundations, pier & beam foundations, and home additions.
Steel piers are the most dependable method of foundation repair, and are often referred to as the "cadillac of foundation repairs". Perma-Pier utilizes the double-walled steel pier, though there are multiple versions available. A double-walled steel pier consists of 2 separate pipes - 2 3/8” and 2 7/8”. Both pipes are ¼” thick, and cut into 1’ sections. '
The sections are sleeved together to create a pipe section 1’ long and ½” thick. The very bottom piece of a steel pier is only 6” long and fitted with a friction reduction pad to ensure a smooth installation process. When these sections are pressed into the ground one after another, they overlap at 6” intervals forming a single continuous and immobile pier.
Once installed, the hollow steel piers are filled with cement-like grout to ensure against upheaval and rust. Steel piers can be locked with steel cable, same as concrete piers. Once this is completed, steel piers are capped and shimmed exactly like concrete piers. Steel piers have a success rate of over 99.9%.