More than hardware store piles

Although Paalupiste introduced helical piles for single-family homes back in 2006, we still get questions from time to time about whether they're really suitable. The confusion often stems from the fact that, in the Nordic countries, many people's first experience with helical piles is the small, hand-installed versions sold in hardware stores. So even seasoned builders are surprised to learn that professional-grade helical piles are available up to 330 mm in diameter, with maximum load capacities reaching around 1,000 kN per pile. For typical detached houses, the load per pile is usually in the 100 to 250 kN range, meaning helical piles can easily support two- or even three-storey homes without any issues.

Why residential builders choose helical piles

The popularity of helical piles in residential construction is growing steadily, and it's easy to see why. They let you skip excavation, spoil removal, frost protection, drainage work, and concrete pouring. Eliminating those steps speeds up the entire foundation process and keeps costs down. In most cases, the only digging needed is to remove topsoil and any organic layers. These are replaced with filter fabric and a thin 150 to 250 mm layer of crushed gravel. Water and sewer lines can often be installed at the same time.

Suitable soil types and spacing

Helical piles perform best in clay, silt, or sand, provided there are no large boulders. For houses, the piles should generally be installed to at least around 2 metres to ensure adequate lateral support. The number of piles depends on the building design, soil conditions, and structural plan, but a typical spacing is 2.5 to 3 metres. That gives you a rough idea for early cost estimates.

The process: soil investigation to installation

The work usually starts with a soil investigation and foundation design. The soil report is essential because it provides the data needed for sizing the piles and preparing an accurate quote. Paalupiste can handle the full package, from design through to supplying the piles and installation.

Installation is almost always done with an excavator fitted with a torque drive head. Before starting, a surveyor marks the pile locations. A reference elevation is also needed so the piles can be set to the correct height. Minor height differences can be adjusted using steel shims inside the pile cap collars. Locations are typically marked with stakes, rebar pins, or spray paint. When using paint (an "X"), make it larger than the pile's helix so it doesn't disappear as the pile is screwed in.

Installation in one to two days

In most residential projects, the piles are installed in one or two days. During installation, torque is monitored either with a sensor or via hydraulic pressure, which requires accurate knowledge of the drive unit's characteristics. Every pile is logged: number, size, length, installation torque, estimated capacity, and any deviations. The client always receives a copy of the installation record.

If large stones affect accuracy and tolerances are exceeded, the foundation designer assesses the situation and recommends any necessary actions, such as additional piles or other adjustments.

The structural frame above the piles

The installer cleans up any cut-off pieces and sends them for recycling. With helical piles, the foundation for a house is completed faster, more easily, and almost always at a lower cost than traditional methods, and construction can begin immediately afterwards. Going concrete-free also cuts CO2 emissions from the foundation phase significantly.

The structural frame above the piles is typically steel or glulam beams. Piles can also support footings or slabs. Pile caps are fitted to the top of each pile and have bolt holes for attaching timber beams from below. Alternatively, a steel frame can be welded to the caps, or the caps can be cast into a concrete ring beam.

The result

In the end, helical piles deliver reliable foundations quickly and cost-effectively while keeping the site clean. If you're planning a new home, get in touch with us at Paalupiste, and we'd be happy to talk through your project.