Our task.

William Hunt Consulting were asked to provide a cost-effective, low-impact solution to a block of flats near Bedford, which was suffering from subsidence as a result of moisture extraction from nearby local authority owned trees.

The trees were located to the rear of the site and had caused category 5 damage to the rear portion of the three-storey structure with cracking of up to 40mm recorded.

Time and cost savings.

Over 12 months

The solution.

Although space was tight to the rear of the building a root barrier was successfully installed to separate the roots of the implicated vegetation from beneath the building and provide long-term confidence that the property would remain unaffected by these trees. The barrier was successfully installed within one week.

Due to the severity of movement to the property; significant deep-seated desiccation of the clay soils; and likely timescales involved in allowing the clay to rehydrate naturally, stakeholders had been preparing for a period of approximately two years to allow the ground to rehydrate before repairs been with just natural rehydration.

The result.

There were a number of benefits resulting from the root barrier and Accelerated Rehydration solution. The implicated trees to the rear of the site that offered a screen from a nearby road, were retained. The time periodfor ground recovery was more than halved which not only reduced disruption to the tenantsbut had a significant cost reduction impact on the alternative accommodation costs.

Had the trees remained in situ the conventional solution would have been to complete an underpinning scheme to the structure.

The cost of this work together with all other associated costs would have been in the region of £160,000. The total cost of the dual root barrier and rehydration was under £30,000.