Helical Piers Installation FAQ
Q. What is a helical pier?
A. A helical pier is a steel pipe or square bar with plates on the end. The helix-shaped plates are welded to the steel pipe / square bar, making the assembly resemble an auger.
Q. What do helical piers do?
A. They hold up, vertically, a load placed on them, like a foundation, tower, etc. In horizontal, they resist lateral loads such as a retaining or basement wall that is tipping or a tower’s guy wires.
Q. How much can they hold?
A. Depending on the pier design and soils, any amount up to 160,000 lbs.
Q. Can they be installed in the winter?
A. Yes. Some weather conditions are too extreme for installation, but helical piers are very versatile and may be installed in most conditions.
Q. How long do they last?
A. Properly designed, they last a very long time. Soil types, fluctuating water tables, and contamination can affect their life expectancy. Engineers are not confident of predicting steel in the ground beyond about 50 years. That does not imply 50 year life. Current experience is excellent with very minimal failure. The residential use of helicals is approximately 25 years. Utility use is far longer with excellent results.
Q. Can piers actually lift foundations?
A. Yes, if properly designed and installed. However, this doesn’t guarantee 100% recovery of any cracks that show up on walls. Just because they’re capable of lifting doesn’t mean they always should. The main goal is stability–to stop foundation movement in a repair situation. If we put too much upward pressure on a house, trying to force it back the way it was, it could cause more damage.
Q. How deep to helical piers go?
A. Most are installed 10-25 feet below the soil, but may go 100 feet or more if necessary.
Q. How big is the installing equipment for helical piers?
A. Most of our helical piers are installed by hand-held equipment. Occasionally, a mini excavator is appropriate.
Q. How disruptive to the yard and grounds are helical piers?
A. Disruption is very minimal. Typically a 3 foot by 3 foot hole dug down to the footing is adequate.
Q. Do piers damage the interior of the house during a lift?
A. More often than not, no. In fact, cracks can close, doors and windows can work like they should, etc. In the event of intermediate remodeling, it is not unusual to encounter the risk of cracking and distorting adjusted doors. In the later event, many home owners elect to stabilize only.
Q. Are helical piers the only solution?
A. Because helicals get their capacity from deep stratum, below the looser soils allowing the settlement, virtually no other process is commonly used for deep, long-term support.
Q. Does any independent organization test piers?
A. Yes. The industry, in 2007, established the ICCES AC358 ACCEPTANCE CRITERIA FOR HELICAL FOUNDATION SYSTEMS AND DEVICES. This is a rigorous, time consuming, costly process of testing, analyzing, and reporting of pier design, testing, and performance. This application is submitted to the ICC. They refer the application to a national, independent testing engineering firm. Their job is to confirm that the piers and related devices perform up to expectations and designs. This 6 month process is followed by more reporting and review. Upon completion, the product is declared as having passed the criteria. At this time, MacLean Dixie of Birmingham, AL is the only manufacturer to have received these credentials for their multiple lines of helical piers. One other manufacturer has received approval for one pier. Clearly, helical piers have tremendous flexibility to be the right, cost effective solution to concrete and poured concrete foundations.