I hear a lot about different helical pier systems. What sets A.B. Chance apart from the rest?
A.B. Chance has been manufacturing helical anchoring products longer than any other helical pier manufacturer. Their products have the recognition and acceptance of all the major U.S. building codes.
Aren't most of the helical products in the marketplace comparable in their capabilities?
Not necessarily. Steel quality, manufacturing methods and welding procedures, among other factors, vary widely. A.B. Chance anchoring products have withstood the rigors of virtually every challenging installation condition for decades. Their mechanical ratings have been laboratory tested and time tested. Lesser products can break down during challenging installations, in much the same way lower-quality tools can. Trouble is, it can happen below the ground surface, escaping detection. A.B. Chance hardware is virtually indestructible, even in the face of the most brutal rock, rubble and debris-laden drilling at maximum torque.
Some helical pier contractors advocate pipe-based products, while others believe in solid square-shaft helical hardware. Which is better?
Each type has minor advantages and disadvantages. Generally, either one will work just fine in most situations. Pipe-type helicals can hold their capacity better in extremely soft soils offering low shaft support. Square-shaft helicals can be more resistant to damage from rocky or obstruction-laden, high-torque installations. Solid square-shaft helicals can also have much better resistance to corrosion.
Should I be concerned about corrosion and corrosion protection when I'm considering steel foundation support piers?
Yes, particularly in situations where there is new construction in poorly-consolidated fill material. Ultimate settling of soils under and around footings, grade beams and floors creates air-spaces which can also harbor water – providing a haven for rust and corrosion. Stand-alone structures supported on helical piers, such as walkways, docks and machine bases can leave exposed shafts vulnerable to corrosion at the ground line. In these situations, hot-dip galvanized helical piers are a must.
Why do solid square-shaft helical piers offer greater resistance to corrosion?
Unlike hollow, pipe-based products, solid square-shaft piers can corrode only from the outside inward. With hot-dip galvanizing and the addition of a drawn-down grout column, any potential for corrosion is all but eliminated.
Aren't most helical piers components furnished with some kind of serious corrosion protection?
Not necessarily. Some are coated with clear lacquer, painted or powder-coated. Some are even sprayed with silver paint to appear as though they’re galvanized. Make sure you ask!
I have quotes from different contractors who are proposing varying numbers of steel piers to support the same area of my building. Who is correct?
There is no exact science to designing underpinning or new construction support with helical piers. The ability to save money on piers by increasing the span between them depends upon the weight and integrity of the structure. Another factor is the engineer’s and/or contractor’s comfort level with the design and their willingness to offer a long term warranty. More support piers of comparable capacity within the same area translates to a greater margin of safety. If a contractor is proposing a project with significantly fewer support piers, he should have the engineering and warranty to back it up and there should be a significant bottom-line cost savings to you.
I have an existing building that's experienced considerable settling. There are sizable cracks and the floor is out of level. One contractor claims he can close the cracks and "level everything up". The other is apprehensive about promising such an outcome and is advising me to exercise caution. Who is right?
Be careful about awarding an underpinning contract to a contractor based upon their promise of a lifted, “leveled” structure. In most cases, it’s much safer and more realistic to lift slightly to stabilize a structure in place than to attempt major corrective jacking using steel piers. Over-zealous jacking can create peripheral and hidden damage, as well as lifting portions of the building beyond the boundaries of the underpinning piers, setting the stage for future movement in those newly-unsupported areas.