Subsidence Investigation in Co. Galway

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This project was completed on behalf of a major insurance Company. The brief was to complete a series of investigative works as prescribed by a Consulting Engineering Firm to confirm if and why the cracking was related to foundation movement or subsidence. Substruck Ltd. regularly complete this type of investigation work all over Ireland on a regular basis. We are one of the very few firms in Ireland who can genuinely offer a full set of inhouse specialist investigative techniques.

The scope of works were as follows:

  • Hydrostatic Drain Test & CCTV Survey,
  • Plumbing, Heating and Water Supply Test,
  • Trial Holes,
  • Installation of Crack Monitors and
  • Chemical analyis of water samples.

A two-storey rear extension showed the classic signs of rotational movement away from the original structure. Cracking was noted at the junction of both buildings. These cracks which were wider that the top. Cracking was also noted along the junction at ceiling level.

The drainage was somewhat unorthodox. One part of the system was simply formed with a gully hopper connected to a junction via a 100mm drainpipe. Therefore, it did not possess a trap. Building Regulations require a trap to prevent foul odours from entering the building. The downpipe feeding this drain did not terminate below the grid. It discharged simply to ground. Therefore, the benching around the gully was relied upon to ensure that the water reaches and enters the drain. Not only that, the connection between the hopper and the drain pipe was not appropriate and a test on this localised section failed (no surprise!!!). Water escape was visible between the hopper and the pipe.

A full report was provided to the Consulting Engineer on completion.