Efficiencies in Digging
For one of our current projects, we are trying a different system for digging the footings for a front porch and staircase in Arlington, MA.
Screw pile foundations are certainly not new. This technique has been used since the 1800’s and is typically used in climates where the frost line is very deep in the ground (Canada, for example). The process involves using an excavator (or similar machine) equipped with a rotary hydraulic attachment that winds a large screw-in piling and anchoring system into the ground. Picture a screw going into a piece of wood, but on a larger scale.
Benefits of the screw pile method –
It’s quick! - It takes hours, not days, to complete. Each hole takes about 10 minutes to complete. The best part is that you can start framing immediately afterwards.
A typical footing consists of digging holes 4 feet deep underneath where each supporting post will go. Before you can pour any concrete in the holes, you must leave them open and exposed to be inspected by your town’s building department.
While you are waiting at the mercy of the inspector’s schedule, consider this - leaving a 4 foot deep hole exposed is dangerous, to the construction team, as well as homeowners, neighbors, animals, etc.
Once you have the OK to continue, you can then go buy, mix, and pour the concrete to the correct height. While the concrete is setting up, you add in the metal anchor (which will hold posts) at the top of each hole, making sure everything is level. Come back the next day when it’s fully dry, and then you can backfill the holes around your footings.
It’s less messy! – Moving 4 feet deep worth of soil is a lot of dirty work. When you remove the soil from the hole, you also need a place to put it temporarily, so you are disrupting landscape in the surrounding area.
Screw piles torque into the ground like a giant screw. There is little to no disruption to the soil, which is a good thing in terms of ground settling too. It’s eco-friendly too!
It’s cost-effective! Need we say more on this point? Everyone wants to save a little money, contractors and homeowners alike.
Here is an illustrated example of how these pilings are installed.
As you can see below, when the pilings are installed, they can be at different heights sticking out of the ground. We will cut the shaft to the correct height needed for each post to sit on.
Close up of top view.