Case Study

Fort Dunlop

The largest office building outside of London and a 100 bedroomed hotel nearly didn’t make it out of the ground.

It came to light very late on in the design process, that Severn Trent Water had two main sewers running through the site. The exact whereabouts was unknown but they were thought to be deep.


Using a combination of techniques, a SUMO survey found them exactly “Nerves were on edge... the development was saved!”

MD - Taylor Wimpey


What Happened

  • Design was fixed, construction contract awarded and ready to start.
  • Late discovery of records hinted at major sewers under the site but location was vague.
  • Possibly under building footprint. Diversionary costs were potentially £100,000’s.
  • “Cross your fingers and hope for the best” approach was not an option.
  • Construction programme halted. Re-birth of the site after 20 year wait at risk.
  • Depth of sewers beyond the detection range of non-invasive techniques.
  • Taylor Wimpey called on SUMO to devise plan to locate them.
  • Sewers located exactly and at 7.0 metres deep away from the building footprint.

The Savings

Savings were made in time, money and risk. The non-invasive survey cost was £5,000. It resulted in savings of £100,000’s.

  • The SUMO Solution and Benefits
  • Devised best value solution, which dramatically mitigated the financial risk.
  • Kept trial holes costs to a minimum saving £100,000’s.
  • Confirmed the development could safely continue on schedule.
  • Detected further unknown water main thus avoiding potential service strike.

Some Fascinating Facts

Fort Dunlop was once the world’s largest factory. During the construction period it had the largest permanent billboard in Europe. The roof is transformed into one of the largest living green roofs in the country.


Survey techniques used in this case study...

SUMO Survey
Utility detection
& mapping

Ground Probing Radar (GPR)

Electromagnetic Location (EML)