Case 1

Cause of Defects

The pattern and distribution of the damp mark appeared to follow the poorly insulated chiller pipes and stop at the turn the pipes. As it appeared on both the wall, beam and ceiling, it is unlikely that the cooling of the ceiling has been caused by the air-conditioned slab from the floor above. It must be noted that along the wall, the damp mark did not stretch through the whole height of the wall but rather confined to areas around the chiller pipes. However, the air-conditioned level L1 slab would have aggravated the condensation problem. (Dew point measurement was made using the infrared thermography and temperature and humidity measurement of the ambient environment within the inspection shaft.)

Part of the wall separating the media room was backfilled with soil and the presence of a layer of  a black waterproofing membrane below the soil level was evident. The soil appeared saturated due to the seepage of water from an opening found in the opposite wall, i.e. wall separating the Inspection shaft and planter box / front garden. Some of the excavated soil is left in the Inspection Shaft and formed into an embankment. Water seeping through the opening saturates the soil embankment. The soil condition contributes significantly to the high humidity in the ambient air.

The waterproofing layer below the soil level may prevent the ingress of moisture from the damp soil through the concrete wall in level B2 and B3. As the surface above the soil level is not waterproofed, and considering the high RH in the shaft, high rainwater ingress into the shaft, inadequate drainage and severe condensation and wetness on the wall, floor and ceiling, long-term watertightness of the elements concern is doubtful.