Pile calculator
How many screw piles do you need?
Choose your structure, enter the dimensions and instantly see an indication of the number of screw piles, the pile type and the layout.
Indication
—
This is an indication, not a Eurocode 7 design. For your quote we review your plans and the soil, and we measure the bearing capacity of every pile during installation.
How do we calculate?
- Imposed loads according to the Belgian national annex NBN EN 1991-1-1 ANB: 2.0 kN/m² for terraces and floors (homes), 4.0 kN/m² for balconies, raised terraces and jetties.
- Snow according to NBN EN 1991-1-3 ANB: 0.5 kN/m² on the ground (up to 100 m altitude), × 0.8 on the roof. On roofs up to 20° we use at least 0.8 kN/m² maintenance load.
- Self-weight from the unit weights in NBN EN 1991-1-1 annex A: decking ± 0.2 kN/m² plus the beams, log cabin walls 0.12–0.15 kN/m², light roof with felt or EPDM ± 0.3 kN/m², open pergola ± 0.15 kN/m². For insulated buildings: timber floor 0.6, timber-frame walls 0.5–0.6, flat roof 0.6 and tiled roof 0.7 kN/m².
- Ground screws or screw piles: for light structures we first propose ground screws (Ø 76 to 114 mm), calculated with the Perko method (shaft adhesion plus end bearing) and an overall safety factor of 2.42 according to Eurocode 7. If they are not sufficient, or for a heavier building, we choose a screw pile, using the calculated bearing capacity from the manufacturer's technical data sheets per pile length and soil type, with a safety factor of 2. All piles and screws go at least 1.2 m deep, below the frost line.
- Terraces: the pile spacing follows from a timber check (C24, outdoor): bending, shear and deflection up to L/300, including creep.
- Supporting structure per type: modular homes, tiny houses and garden offices stand on a ring beam all round, with an extra line of piles under every module joint (modules up to ± 4.2 m wide). Floor and roof bear on the long sides; the short sides carry only their wall. Timber-frame buildings get intermediate lines under the load-bearing walls (every 4.5 m), garden sheds stand on ground beams and carports on beams. The pile spacing follows from the capacity and deflection (L/300) of the chosen beam: steel S235 (HEA 160, UPN 200) or timber C24/GL24h.
- We determine the load on the most heavily loaded pile (corner, edge or centre) and choose the smallest helix that is sufficient.
- Not included: wind (uplift on carports), point loads such as a hot tub or a stove, and friction along the pile. For your quote we calculate from your plans and the soil, and we measure the bearing capacity of every pile during installation.