Why Helical Pier Foundations are a Great fit for your Bay Area ADU. Your Questions Answered.

What is a helical pier?

A helical pier is a steel shaft with helices, similar to a large screw, that provides a foundation support for various types of structures. The shaft is usually Round or square and manufactured in 5 to 7 foot sections. Helical piers are often used when challenging soil conditions prohibit a traditional foundation system. They are also commonly used to correct and support existing foundations that have settled or failed.


Why use helical piers vs traditional concrete foundation?

To reduce carbon emissions and make construction time more efficient, we use helical piles for our SIP lightweight structure. There is no need for concrete formwork, steel reinforcement and curing times (7-10 days), helical piles can be installed on different soil conditions, sloped or uneven ground, in a matter of hours, with an average performance rate of 30 seconds per linear foot.


Advantages of helical piers

  • No excavation, vibrations or spoils

  • Quick installation and can be loaded immediately upon completion

  • Approved for use by building code agencies

  • Easy to use in limited access areas, areas with high water tables, and weak surface soils

Are Helical Piles allowed in my jurisdiction?  Helical Piles we use are ISO and ICC Certified. We chat with your local jurisdiction before work begins to confirm usage and educate if needed.

 How much do helical piers cost? The cost is dictated by the design, size, and weight of the structure and the adjacent soil conditions. The load to be supported dictates the size of the helical pier shaft. The supporting layer of soil dictates how many helices are used for the lead section. We offer free estimates and can give you a better feel for the costs once we understand the conditions specific to your situation.

How new are helical piers?  Helical piers have been around since 1802 to stabilize structures constructed on sand, mud and similar bases.

How deep do helical piers go? Because each helical pier is installed to a specific load requirement rather than a specified depth, each application is different. A typical depth for an ADU is about 12 feet to 16 feet. 

How are helical piers installed?

A hydraulic drive head is attached to a small excavator.

How much space is needed for installation?

Helical piles can be installed in areas as small as a coat closet. We have portable equipment that can be used in very small spaces and larger equipment for open spaces. Compared to other pile and pier methods our equipment is relatively small and less intrusive.

How will the installation impact my yard and landscaping? We typically put plywood on the landscaping and grass to protect it from our equipment, and are very careful around any building. Some landscaping may need to be removed to gain adequate access to problem areas of foundation. At the time when we provide a free estimate, we can identify any specific impacts to existing landscaping.

How long does it take to install helical piers? All 10-16 helical piles in our ADU’s can be installed in a day. With existing structures, usually four to 8 can be installed in a day.

How long will helical piers last in the ground? Will they rust?

Helical Piers are coated with the latest galvanizing known to the industry. This protects the piers from rust and corrosion. In most soils there is a life expectancy of over 150 years or more. 

Do you install other types of deep foundation systems? Yes, in certain situations we would use precast concrete footings to support your structure instead.

Why are the helices only on the lead section?A: Because the helices carry the load of the structure and you want that load supported by the best soil available. This is called ‘true end bearing capacity’.

Call ADU Works Today: 408-610-3005