When building a deck, one of the most important things to consider is how to secure it to the ground. Typically, concrete footings are used to secure decks, but in more recently, helical piles have emerged as an alternative. Both methods have their advantages and disadvantages, depending on the specific needs of the project. Let's explore what helical piles are, how they are different from traditional concrete footings, and the benefits of each when building a deck.

What is a Helical Pile?

A helical pile is a type of foundation system that consists of a steel shaft with one or more helix (spiral-shaped) plates welded to it. These piles are screwed into the ground using specialized equipment that rotates the pile into the soil, similarly like drilling a screw into wood. Once the pile reaches a sufficient depth, it provides a stable anchor for the deck structure.

Helical piles are often used in areas where traditional concrete footings are difficult to install, such as wet or unstable soil, or where there is a concern about environmental impact. They are designed to carry both vertical and lateral loads, making them an excellent option for supporting heavy structures like decks.

What is a Concrete Footing?

A traditional concrete footing is a poured concrete base, typically formed in a sono tube that serves as a foundation for supporting the posts or beams of a deck. Concrete footings are usually placed in holes dug into the ground and then filled with concrete to form a solid, stable foundation. These footings must be installed below the frost line to prevent them from shifting due to freezing and thawing of the ground. Here in Ontario, that's a minimum of 4ft.

The installation of concrete footings typically involves drilling or digging, pouring, and waiting for the concrete to cure before any deck construction can begin. The size of the footing is often determined based on the weight of the structure and the type of soil. Here in Ontario, we use 75kpa as the base point for the type of soil. If they ground is very firm or hard, a soils engineers report can be completed to find the exact loading capacity of the ground. If it is determined that the soil is very firm or hard packed, footings can be smaller and/or spaced farther apart. Since, those reports can be quite expensive, most decks are just assumed worse case scenario, and 75kpa is used for this number.

How Are Helical Piles Different from Traditional Concrete Footings?

1. Installation Method

  • Helical Piles: These are mechanically screwed into the ground with minimal digging required. The installation is faster, and the piles can be installed in a matter of hours, depending on the size of the deck. Decks can be installed immediately after installation. There is no excess fill to remove from the job site.
  • Concrete Footings: Traditional footings require excavation—typically auger drilled holes, pouring concrete, and curing time, which can take a full day or longer to complete. This is a more labour intensive process.

2. Soil Requirements

  • Helical Piles: They can be installed in a variety of soil conditions, including wet, soft, unstable, or rocky soils. This makes them ideal for areas where it’s difficult to dig deep enough for traditional footings.
  • Concrete Footings: Concrete footings require stable, firm soil for installation. In some cases, they may need additional reinforcement if the soil is too loose or unstable.

3. Foundation Type

  • Helical Piles: They are installed deep into the ground, reaching stable soil layers, and provide a foundation that is highly resistant to movement. They work well in areas prone to shifting or settling soil. A torque monitor on the machine measures the torque required to install and through some math calculations, a bearing capacity is determined. After 4ft, if adequate bearing capacity has not been achieved, the piles can continue to go deeper, even adding additional extensions until the desired bearing capacity is achieved.
  • Concrete Footings: Traditional footings rest can only go as deep as the excavating equipment can reach.

4. Environmental Impact

  • Helical Piles: Because they are installed with minimal disturbance to the ground, they are considered more environmentally friendly than concrete footings. The installation process creates less noise and disruption, and there's no need for concrete mixing or large excavation and excess fill removal, which reduces environmental impact.
  • Concrete Footings: The installation of concrete footings involves digging and transporting concrete and the excess fill, which can have a higher environmental impact, especially in sensitive or natural areas.

Benefits of Helical Piles for Deck Building

1. Quick Installation

  • Helical piles can be installed much faster than traditional concrete footings. Since they don’t require curing time or extensive excavation, your deck construction can start more quickly.
  • If you want to get your deck built as quickly as possible, helical piles reduce wait times and allow for faster progress.

2. Suitability for Wet Soil Conditions

  • Helical piles are a great solution for areas with wet soil conditions, or areas where traditional footings would be challenging to install.
  • If your property has poor soil conditions or challenging terrain, helical piles allow you to install a stable foundation without the need for extensive ground preparation.

3. Less Disruption

  • The installation process for helical piles requires very little excavation, meaning there is less disruption to your yard or landscaping. This makes them a good option if you want to avoid damaging your lawn, garden, or other landscaping features.
  • If you want to build a deck without disturbing your landscaping or property, helical piles are a great alternative to traditional concrete footings.

4. Adjustable for Future Modifications

  • If you need to modify, expand or remove your deck in the future, helical piles are easier to adjust than concrete footings. The piles can be re-torqued or adjusted to accommodate changes in the deck’s design or load-bearing requirements. They can be easily removed altogether by just unscrewing them out of the ground.
  • If you plan to expand your deck or add new features later on, helical piles offer flexibility for future adjustments.

5. Minimal Maintenance

  • Once installed, helical piles require no maintenance. They are made of galvanized steel, so they can last for for many years without worrying about issues like cracking or settling.
  • If you want a low maintenance, long lasting deck foundation, helical piles offer long term durability with minimal upkeep.

Benefits of Traditional Concrete Footings for Deck Building

1. Proven and Reliable

  • Concrete footings have been used for many years and are a tried and true method of providing stable support for decks. Their reliability makes them a trusted option for many homeowners and builders.
  • If you’re looking for a traditional foundation system, concrete footings offer peace of mind with their long history of use in construction.

2. Cost-Effective

  • For simpler deck designs and stable soil conditions, concrete footings can be a more affordable option compared to helical piles. They’re generally less expensive to install in and don't require an engineer's stamp.
  • If you’re on a budget and your property has stable, dry soil, concrete footings can be an affordable option.

3. Local Availability

  • Concrete and the equipment required for pouring footings are widely available, making it easier to find contractors who can perform the work. For small jobs, concrete can be purchased in bags and mixed on site or for larger projects, a concrete truck can deliver ready-to-pour concrete.
  • If you are building a DIY deck, trying to keep costs down, this may be the easiest and most affordable option as bagged concrete is ready available at all lumber yards.

4. More Common for Residential Projects

  • Since concrete footings are so commonly used in residential projects, most contractors and homeowners can install them without specialized help.
  • For many homeowners, the familiarity and widespread use of concrete footings can provide peace of mind at an affordable cost.

Which is Right for Your Deck?

Both helical piles and traditional concrete footings offer their own unique advantages when building a deck. Here's a quick guide to help you decide:

  • Go with Helical Piles if:
    • You have wet soil conditions (or rocky, loose, or sloped land).
    • You want a faster, less disruptive installation process.
    • You prefer a more environmentally friendly solution.
    • You’re looking for a durable, long-lasting foundation with minimal maintenance.
  • Go with Concrete Footings if:
    • Your soil is stable and well-suited for traditional footings.
    • You’re on a budget and want a cost effective solution.
    • You’re building a DIY deck.
    • You prefer a tried-and-true foundation.

Ultimately, your decision should be based on the specific conditions of your property, the design of your deck, and your budget. Consulting with a contractor or deck professional can help you choose the best foundation for your needs.