Helical Piles vs. Concrete Foundations for Decks
One of the most overlooked, yet most important aspects of building a new deck is the footing or foundation. After all, a deck is only as good as the foundations it is built on. This becomes increasingly true when building a deck in areas with drastic temperature fluctuations and harsh winters, such as here in Southern Ontario. Improper foundation selection or installation can result in the need for costly repairs or can lead to the premature failure of the deck. A deck can be a significant investment in many homeowners’ lives. It’s important to understand the foundation options available to you in order to maximize the lifespan and potential of your investment!
Types of Deck Foundations
There are two main types of decking foundations available to consumers today. The first option is traditional poured concrete footings. Poured concrete footings have been used as deck foundations for decades, and when done correctly, are an excellent choice in many situations. Poured concrete deck foundations can last for many decades and most often outlive a pressure-treated deck built on them. The second type of deck foundation available is helical screw piles. These screw piles are used in the construction industry to support anything from small lighthouses to large civil engineering projects. Each foundation type comes with unique characteristics and traits that homeowners seeking a new deck can benefit from knowing! Rest assured in knowing that whatever foundation style you need for your new deck, Align Decking will do it right, the first time.
Poured Concrete Deck Foundations
Deck posts mounted into their saddle brackets on poured concrete foundations.
Poured concrete foundations are installed by first digging boreholes into which concrete will be poured. The number of foundations, their diameter, and placement will be job-dependent as each building site has unique characteristics. Once all of the foundation holes are bored out to the appropriate diameter and depth, and their locations are confirmed, concrete is mixed and poured into the holes. Saddle brackets are then cast into the wet concrete which will become the mounting points for the deck posts.
Things to Consider
Poured concrete foundations are a reliable foundation choice used in deck construction all across the globe. That being said, there are some things to consider before selecting them for your next deck project. Firstly, there are some situations where poured concrete just won’t work, like in areas with poor drainage. Also, sometimes even when everything is done correctly, concrete foundations can fail and heave. These failures are extremely rare but it’s something that should be noted. Here are some other points to consider when selecting concrete foundations:
Installation can be time-consuming. A waiting period is required between pouring the foundations and building the deck.
Installation is weather-dependent, concrete foundations cannot be installed in the winter, rain, or in conditions where the ground is water-saturated.
Larger foundations can sometimes sink due to their weight, albeit very rarely.
Foundations can sometimes heave due to frost, albeit very rarely.
Installation causes soil disturbance and can be damaging to root systems.
Excavation of holes creates the need to dispose of or relocate soil.
Cannot be installed in areas with high water tables.
Helical Screw Pile Foundations
Installation of helical screw pile foundations
Helical piles or screw piles are essentially steel cylinders with a large helix anchor on the end. Helical piles are used in all types of building construction, small and large, and are often referred to as the most important development in geotechnical engineering of the mid-late nineteenth century. Although many refinements have been made in the 170 years since the creation of structural screw piles, the basic premise remains the same.
Screw piles have many advantages over poured concrete deck foundations, with their flexibility of installation being the largest benefit. The ability to install screw pile foundations in areas where concrete foundations are not possible allows us to build decks for clients in spaces otherwise thought to be impossible.
One of the greatest misconceptions about screw pile foundations is their cost. Many homeowners assume that screw piles are much more expensive than poured concrete foundations, which isn’t always the case. Many factors impact the cost of installation, but in some instances, the price difference between screw piles and poured concrete for a given job can be nominal! During our initial consultation and planning phase, our experts will assess your building site and determine the best foundation for your yard’s unique characteristics, and your budget.
Things to Consider
Installation is rapid, saving time and money.
Screw piles can be structurally loaded immediately after installation, meaning deck construction can proceed right away.
No excavation or removal of soil is necessary; more environmentally friendly.
Installation is not weather-dependent. Screw piles can even be installed in the middle of the winter!
Ability to add a cathodic protection system to extend the life expectancy of the screw piles.
Can be installed in areas with high water tables.
Can be installed in a variety of marginal soil conditions.
Will never heave or sink.
Deck Foundation Pros
In some rare circumstances, neither poured concrete nor screw pile foundations will be suitable for your deck project. An example might be someone seeking a deck in cottage country along the Canadian Shield, where in many areas, the bedrock may be only a few inches below grade. In situations like this, ICFs (Insulated Concrete Forms) may be used as forms to pour piers directly onto the bedrock. Another solution may be to drill into and install saddle anchors directly into the bedrock which are then set with epoxy.
Because each situation is different, our team will need to evaluate the building site to determine an appropriate solution for your unique foundation needs.
Regardless of the foundation chosen for your deck project, rest assured that Align Decking has the knowledge and experience to get it done right, the first time. We have over 15 years of experience installing foundations for decks of all types, in all weather and seasons, and in a variety of ground types! Put Ontario’s deck foundation experts to work for you today!