Hull Minster Groundworks Project



We recently delivered LECA® LWA to England's largest parish church Hull Minster with our unique pneumatic delivery facility.

We recently delivered LECA LWA to England's largest parish church Hull Minster with our unique pneumatic delivery facility. Overcoming difficult access to this Grade 1 listed building and delivering at a rapid speed, which was crucial for this groundwork repair. This delivery option significantly reduced man power and also ensured that safe social distancing measures could be maintained. 

For this project, LECA LWA 10-20 aggregate was pneumatically blown in as backfilling material following archaeological excavation works at Hull Minster. LECA LWA was specified for the groundwork repair because of its lightweight properties and its ability to tackle the possibility of mechanical compaction of the top layer and to reduce the settlement to external areas where paving was proposed to be laid. 

For this project, the designers required around 130 Cu/m which included a compaction reduction of 10%. The intention of the project was to carry out backfilling of archaeological excavations up to the formation level and for it to remain whilst further works are carried out over a few months.

LECA LWA was deemed as a suitable solution furthermore due to the pre-compaction of LECA LWA, which expected to be 5%. Moreover, as LECA LWA requires little compactive force, any sufficient load placed on the compacted material will force the particles into place. 

Furthermore, as good compaction was required for the final build, on a depth between 300mm and 600mm – using LECA LWA only required 3 passes of the Light Vibrating wacker plate, which effectively ensured that the material sat in its final resting place. (We often state that compaction is not necessary if the depth is below 300mm, as any capping above will normally force the material in to place.)