Decks in Canada rely primarily on the foundations themselves due to Canada’s difficult soil conditions, seasonal temperature fluctuations, and severe freezing-and-thawing (or frost) cycles. Traditional concrete foundations (footings) cause problems, particularly in instances where soils heat and expand when snow melts in spring. This is why many homeowners and contractors have utilized helical deck footings throughout Canada, for their reliability, speed, efficiency, and code-compliance.
What Are Helical Deck Footings?
Helical foundations (or helical piles, screw pylons, or helical piers) exist as a steel shaft with a helix-type plate (usually 3 or 4) that connects to the shaft and provides support for the steel shaft when the helical foundation is installed. The helical shaft is installed by being mechanically screwed into the ground using hydraulic equipment, to load-bearing layers of soil below frost, and thus create an adequate, stable foundation that is unaffected by the movement of surface soils. Additionally, helical foundations require minimal site disturbance, as they can be installed with no earthwork, cement mixing, or time spent waiting for concrete to cure after installation.
The Canadian Climate Challenge
Unique challenges are presented to building concrete foundations in Canada because of its extreme climate. In central Canada (Ontario, Quebec, British Columbia), frost levels vary between 1.2 metres and over 2.4 metres throughout Canada, depending upon the region of the country. Foundation footings will heave upwards due to the freezing and thawing of the earth when footings do not extend below the frost line into the non-frosted earth. This changeable movement can crack or otherwise break the foundation footings themselves, resulting in the deck becoming misaligned or uneven when ultimately constructed, leading to significant risk of structural failure over time.
Why Helical Footings Outperform Concrete
Helical deck footings eliminate the heaving of concrete foundations by anchoring into stable earth/bedrock well below the frost line. They are installed by driving/installing into the earth/bedrock without any time spent waiting for cured concrete to install (helical deck footing installation and deck framework can be performed within hours of helical deck footing installation).
Helical foundation support systems offer flexible properties; as a result, they can accommodate movement of the ground beneath the deck by yielding with the ground, yet, the helical foundation support system does not transfer the yield stress to the structure above, thus preserving the structural integrity of the structure for each freeze-thaw cycle.
Additionally, helical foundation support systems can be installed in any climate/season throughout the year, including the winter months when it is difficult to install concrete due to temperature restrictions and in Canada’s shortened construction season will allow projects to begin and finish earlier within the year.
Environmental and Practical Advantages
Helical footings have an ecological footprint and practical (less dig up of landscape), will not mess up landscape/soil or disturb underground utilities when they are installed. If a deck is taken out later or changed around, helical footings can be taken out and moved – this cannot be done with concrete footings as they are not made to be moved after they have been installed. Therefore, for homeowners that will eventually be changing their outdoor living space, helical footings will give them the flexibility and sustainability they need.
Code Compliance and Load Capacity
In addition to this, both Canada’s National Building Code and all provincial building codes fully comply with helical deck footings. Such footings can be designed for any specific load and can be tested (torque values) onsite to ensure they hold the weight required before the decking part is framed out. Due to the quickness, reliability, and durability of helical deck footings, they offer the fastest, most reliable and weather-resistant foundation to build on in Canada.
