Quality on a waterproofing job is not just "no leak today". It is whether the work, the materials and the documentation hold up to inspection. In Singapore, the two reference frameworks are BCA CONQUAS for completed buildings and the BCA Quality Mark for individual residential units.
What CONQUAS measures
CONQUAS is a project-level scoring system covering architectural, structural and M&E elements. Waterproofing sits under the architectural component, with wet-area water-tightness as a specific sub-assessment. CONQUAS uses a sampling regime — only a percentage of wet areas is tested, but each test is documented and counts towards the project score.
What Quality Mark measures
The BCA Quality Mark is unit-by-unit. Every assessed unit is checked for water-tightness, finish quality and defects. For a developer pursuing Quality Mark, every bathroom on every floor has to pass — there is no sampling. The contractor side discipline is therefore higher.
The wet-area water-tightness check
The check is a ponding test, usually 24 hours, on the floor of the wet area before tiling. Water level marked, kept constant by topping up if evaporation is high, checked at 24 hours. Adjacent rooms checked for new ingress. Pass criteria: no level drop beyond the evaporation allowance and no new dampness in adjacent or below spaces.
Documentation that the assessor expects
- Membrane product data sheet and current test certificates
- Method statement matching the on-site sequence
- Photographic record at substrate, first coat, second coat, ponding test
- Signed-off ponding test record per unit
- Re-test record where a unit fails
Common failures at assessment
Wet-area failures cluster at the same details — membrane stops short at wall upturn, pipe collar missing, floor trap upstand not encapsulated, ponding test missing from the record. The product is rarely the cause; the detail is.
How quality control fits the contractor side
Quality control on waterproofing is not an inspection that arrives at the end. It is a discipline of substrate, membrane, detail, test and record at every wet area. The framework — SS 637, CONQUAS, Quality Mark — gives the language. The contractor side gives the actual film thickness, the actual collar, the actual ponding test record.