Do I need Piles for my Deck in Saskatoon?

We often get clients asking us what the best foundation is for their deck project. Do I need screw piles? Is concrete the only good option? Sure, there is lots of information on Google and YouTube, but most of it is published by people around the world. Here is Saskatchewan, we have very different requirements than places like Texas or even Ontario. The long stretches of sub-40-degree weather cause the ground to freeze deep. Depending on the year, the frost depth can reach 8-10ft. These unique conditions demand special attention when creating a foundation. We are here to clear up the confusion and show the different options that are accepted and suitable for our climate.

Screw Pile

The most common option for a permanent foundation in Saskatoon is a helical screw pile. These are professionally installed with specialized equipment and stamped by a licensed engineer.

When installing, the machine twists the screw-like object 10-15ft into the ground. This ensures it has the required load bearing capacity and is below the frost line. This provides a permanent foundation that is not going to ever move or shift.

So why wouldn’t everyone opt for this? Although we suggest you do, the main drawback is the higher cost. Screw piles range from $250-400/each. That price includes the product and the installation.

This decision between these foundation options is a lot easier if the deck is more then 6ft off the ground. In that case, the city of Saskatoon requires you use a permanent foundation. Screw piles are also required if you have any roof structure or patio cover. These structures can catch the wind and cause the deck to lift off of its foundation. This has the potential to damage the deck or cause safety concerns. Screw piles – in addition to providing the necessary compressive strength will also resist any tension caused by uplift.

Pad and Adjustable Base

For this method, the ground is tamped. Then a concrete paver is placed on top. The pad carries the load from the deck and disperses it into the ground. An adjustable base is attached to the post and the assembly rests on the centre of the pad.

This option is very popular due to its low cost. The entire assembly is typically less than $40. For most applications this option is sufficient and works well. However, there are a few drawbacks.

As the ground freezes, water in the ground expands and forms ice lenses. This causes the ground to heave and shift. This in turn shifts the deck and moves it out of level. During the spring, when the ground thaws, the deck will often not return to the exact same position. An adjustable base (like the GH Leveller) can be used to move it back to the correct position but expect to have to go out with a wrench every 1-2yrs to re-level the deck