Façade Retention in Central London: Temporary Screw Piles Near Trees
| Application | Façade retention (temporary works) |
| Location | Central London, United Kingdom |
| Piles | Helical, Ø139.7 + Ø88.9 mm |
| Pile length | 6 m and 8 m |
| Accuracy | ±5 mm position, ±2 mm levels |
In Central London, UKHelix installed Finnish-made helical piles to carry a temporary façade retention frame, the steel structure that holds a building’s frontage safely in place while work goes on behind it. The job sat right next to trees, so a foundation that could go in, and later come out, without disturbing the roots was exactly what the site needed.
This is where screw piles earn their keep on temporary works: they are wound into the ground with no excavation, and once the frame is no longer needed the piles can simply be wound back out. UKHelix used a mix of Ø139.7 mm and Ø88.9 mm helical piles, taken down to 6 and 8 metres, and comfortably exceeded the torque the project called for, even on the deepest 8 metre piles.
A steel holding frame leaves no room for guesswork. The 200 mm beams sat on 250 mm top plates, which allowed 50 mm of setting-out tolerance, but the crew worked far tighter than that: pile positions to within ±5 mm, vertical alignment to ±5 mm, and the top plate levels to ±2 mm. It is not often screw pile foundations are held to steelwork tolerances, and these cleared the bar with room to spare.
Working this close to trees, on a sensitive Central London site, the screw piles gave the frame a precise footing that comes straight back out once the work is done, in and out without leaving a mark on the ground.
