Overview
This article provides a practical guide to helical piers, explaining their function, advantages, costs, and typical installation considerations for foundation repair or support in residential and commercial construction.
What Are Helical Piers?
- Helical piers are steel foundation posts with attached spirals that screw into the ground for structural support.
- They work best in loose or water-saturated soils and are less effective in rocky conditions.
- Installation causes minimal landscape disturbance and provides immediate load-bearing capacity.
Advantages and Suitability
- Helical piers install quickly, require no excavation or concrete curing, and minimize impact on surroundings.
- They offer stability and can prevent foundation settlement issues in unstable soil.
- More cost-effective than some deep foundation systems but may not suit very heavy structures or rock-heavy soils.
- Consulting a structural engineer is advised before choosing helical piers.
Effectiveness and Use Cases
- Helical piers have a long track record in foundation reinforcement since the 1800s and are widely used globally.
- They are especially effective in transferring loads through problematic soils to bedrock.
- Alternatives like pressed pile systems may be more cost-effective in certain markets.
Planning and Sizing
- The number of piers needed depends on structure size, with typical residential needs around one every six to nine feet.
- Larger or multi-story buildings may require more frequent placement to ensure safety.
Installation Depth
- Typical helical piers extend 10 to 25 feet deep, but can go as deep as needed for structural support (sometimes up to 100 feet).
Cost Considerations
- Helical pier installation ranges from $10 to $30 per linear foot, with most piers costing $900 to $1,300 each.
- DIY installation is possible for small projects, but large foundation work requires professional equipment and may cost $2,000–$3,000 per pier.
- Total repair costs for residential foundations typically range from $5,000 to $30,000, depending on size.
Cost Comparison with Concrete
- Individual helical piers are generally pricier than equivalent concrete footings, but lower labor needs can balance costs on large projects.
Purchasing Options
- Helical piers for lighter applications are sold at building supply outlets and online retailers.
- Piers for structural support should be sized according to specific requirements and generally purchased through professional contractors.
Recommendations / Advice
- Always consult a structural engineer to determine the suitability and design of helical piers for your situation.
- Consider soil conditions, load requirements, and budget when selecting foundation solutions.