Starter House, Dunas Golf

In February 2023, Rotopile built the deep foundations for the Starter House at the Dunas Golf development, in Comporta. The building is made entirely of timber, in CLT, and called for a foundation to match: light on the ground and low in carbon.

The site is sandy, in Holocene dune and aeolian sands. At the surface, loose to medium-dense sands with little suitability for shallow foundations; only the deeper horizons could take the building's loads. Turned in by rotation, with no soil removed and no open bores, the piles were not held up by groundwater: no dewatering, no bore walls to stabilise.

The answer combined Rotopile PRO400 and PRO250 helical piles, in Ø101.6 × 8 mm steel shaft, with Ø400 × 10 mm and Ø250 × 10 mm helices and 5.0 m long, designed for 150 kN per pile. Thirty-six piles in all: 12 PRO400 and 24 PRO250, carrying the timber structure down to the firmer sands. Against concrete or micropiles, the solution cut the lengths, the material and the time on site.

Installation used a 16-tonne excavator with a Digga D40 drive head, with no drilling, no excavation spoil and no concrete or grout. With no bores, reinforcement, formwork or concreting, the job was simpler and faster, with a clear saving in time and cost.

The biggest gain was environmental. With no major excavation and no invasive work, the ground stayed almost untouched, with a carbon footprint well below the conventional options, in keeping with the CLT build. And like any helical pile, these can one day be unscrewed, returning the site to almost exactly how it was.

36 helical piles (12 PRO400 + 24 PRO250) · Ø101.6 × 8 mm · Ø400 and Ø250 × 10 mm helices · 5.0 m · 150 kN per pile · one 16 t excavator