Frequently Asked Questions
1. People say "the more I read, the more confused I become about the different types of piers. Can you explain?"
When it comes to pier types, there is no standard terminology and it can be confusing.
It is important that the customer is clear on what type of pier is being offered when comparing bids. Making an informed decision can be the difference between a successful, trouble-free repair and a complete waste of money. There are far too many instances where people have paid more than once to have their foundation repaired.
Key points to differentiate between piers are:
A steel pier is built with all steel. There is no concrete or concrete component associated with the steel pier.
A concrete pier may be steel reinforced and/or include steel shims. A concrete pier with a steel component is not a steel pier. It is a concrete pier with steel reinforcement and/or steel shims (spacers) etc.
2.Why does Accu- lift specialize in the steel pier?
The steel pier is the only method that will consistently reach rock regardless of the depth. The steel pier, when installed properly and using quality materials, is unlikely to ever need any adjustment.
3. Why does the steel pier go deeper?
The steel pier will penetrate deeper because the first section of the pipe has a side friction reducer, which makes the hole wider than the pipe that follows it down. The steel pier pipe is also a smaller diameter than the pressed concrete blocks.
The pressed concrete pier has no side friction reducer and will develop the maximum driving pressure at considerably less depth than the steel pier. The only force available to press either pier is the weight of the building. When it begins to lift, that is the maximum depth for that pier. A point or cone on the first section of the pressed concrete pier won't do much to increase the depth. Most of the
resistance comes from the side friction against the soil. All concrete piers achieve most of their load capacity through this side friction. This is
why, in engineering terms, the concrete pier is referred to as a friction pier.
Another major point to consider is that if a steel pier is not driven to rock, it will not be possible to lift and correct the foundation.
The jack will push the pier deeper until it reaches bearing resistance. Since most of the side friction has been eliminated by the side friction reducer, the steel pier reaches the load bearing strata and is therefore a point bearing pier as opposed to a friction pier.
The pressed concrete pier does not share this self testing characteristic. It takes very little depth in hard soil to gain enough capacity to lift and correct a foundation. The job can be completed at this time, but the foundation might not remain stable as soil conditions change.
4.What is the primary factor to consider in order to assure a successful and trouble-free foundation repair?
Assuming for purposes of this comparison that materials and workmanship are equal among contractors, the type of pier is the primary factor that will influence the long-term performance of the foundation repair.
Here are four pier types that are commonly used:
1. Steel pier- deepest penetration, strongest material
2. Pressed concrete pier- also referred to as cable lock, pressed pile, segmented concrete piles etc. This is the pier that is promoted and highly advertised on TV etc. The typical pressed pier consist of a 6 inch diameter by 12 inch long concrete cylinder, an 18" x 8 "x 8" concrete cap and steel shims(spacers). The cylinders are pressed into the ground one at a time against the weight of the foundation. This pier frequently requires adjustment as soil conditions change from season to season. This is due to the fact that this pier will usually not reach bedrock because of the diameter and the side friction (skin friction and in engineering terms). The term "tested on installation" is often referred to as a feature of the pressed pier. The implication is that the pier is tested to its ultimate assigned load or beyond when it is driven. While this may be true at the time of that installation, when soil conditions change, a "periodic" or "seasonal" adjustment may become necessary (unless the pier reaches bedrock). This means the previous structural cracks will reappear and the landscaping will again be disturbed. This could occur numerous times and frequently does.
3. Concrete drilled pier- Also referred to as a drilled shaft and is a monolithic or one piece pier that is typically drilled to depths in the 9 to 12 foot range. It is poured and steel reinforced on site and requires a five-day curing time before the building can be lifted. In most cases, they do not reach rock and there is significantly more disruption to the yard compared to the other methods discussed here.
4. Helical pier- this is basically an anchor that is screwed into the ground to a predetermined resistance as measured by the torque applied at the hydraulic drill head. The high cost of materials makes this pier less cost-effective. It is not designed specifically to reach bedrock.
5. Are all steel piers the same?
No. There is a wide variance in the quality of the materials and design between contractors. Accu-lift steel piers are built with all new steel and are professionally fabricated by certified welders. Some contractors use "drill stem". This is used pipe left over from oil field drilling operations. The quality is inconsistent and it can be difficult to work with due to contamination and distortion.
6. Is Accu -Lift insured?
Accu-Lift is fully insured with General Liability and Workers Compensation policies. A Certificate of Insurance issued by our insurance company and in your name is available upon request. Note: In order to verify that a contractor has an insurance policy that is in effect, you will need a Certificate of Insurance issued by the insurance company and in your name. Hiring an insured contractor protects you from being sued if a worker is injured on your property or if damage occurs to a neighbor's property. It also covers damage to your property if caused by the contractor.
7. Aren't all foundation repair companies required to carry insurance?
No. There is no state or local requirement for business insurance.
8. How do you determine how much to lift the foundation?
The objective is to restore the foundation to its original position or as near as practical and to stabilize it there without creating additional stress or damage. Physical indicators including doorframe alignment, wall cracks and window edge separations are observed as the foundation is lifted. Floor elevations are monitored and lifting is concluded when the foundation is at its original position or as near as practical.
9. If I need interior piers, what is the procedure? How much of a mess is it?
The exact interior pier placements are determined by the locations of the grade beams, load bearing walls, tension cables and plumbing pipes. The piers must be installed under the grade beams. A grade beam is a much thicker area of concrete as compared to the 4 inch slab. First, the tension cables and/or reinforcing steel are located using an electronic rebar locator. Then the grade beams are located. A 2' x 2' section of the slab is jackhammered out at each pier placement.. The pier is installed and the surface concrete is poured back at the end of the job. Breaking concrete produces a lot of dust. Due to concern for the health of our workers and the subject property, our jackhammers are virtually dust free. This is accomplished with the use of misting nozzles, vacuum cleaners and HEPA air filters.
10. How long does the process take?
Most jobs are completed in 1 to 3 days.
11. Do I need to be home when the work is being done?
No, but during the jacking process, our supervisor will need access to the inside of the building to measure the elevations and observe the progress of the lifting.
12. How often would the piers need to be adjusted?
The Accu-Lift steel pier Is designed and installed to never need any adjustment, but it is easily adjustable if required.