Stiff and Trevillion
Symmetrys were the appointed Structural Engineers for this full refurbishment and re-modelling of a four-bed roomed end of terrace home in Hampstead. Including the addition of a basement with swimming pool & gym and a lower ground floor kitchen extension that is linked to external spaces terracing down to the Hampstead ponds, plus a loft extension.
The refurbishment sought to make the very best of the views over Hampstead ponds that this house enjoys and to open up the interior to increase light and volume.
Following ground investigation, a movement analysis was carried out, we discovered that incredibly soft ground led to significant settlement of the building. To deal with this we designed a stiff concrete box at basement level, which ensured that differential movement would be kept to a minimum. The project would not have been possible without this.
During the works we found excessive bowing of the flank walls, this was due to the soft ground conditions, as well as inadequate tie to the floor plate. Traditionally this would have meant the flank wall being demolished and rebuilt. Symmetrys commissioned a highly accurate verticality survey, and undertook detailed analysis. By tying the existing wall to the floor plates we stabilised the wall. Furthermore, we added counterweights to ensure long term stability will be maintained.