THE IMPORTANCE OF SPECIFYING A MEMBRANE TEST METHOD AT DESIGN STAGE
Membrane products may require a method of Quality Assurance Test upon installation to comply with the manufactures installation requirements. In the past the importance of this test has been overlooked, creating doubt around whether the installation is complete and has the warranty been validated if the workmanship hasn’t been checked. The waterproofing products themselves are good but it is the human factor, the installation that is the variable on every membrane application.
The Auckland City Council now requires a flood or electronic test to be carried out for the waterproofing producer statement.
It is commonly assumed that the Quality Assurance test is the responsibility of the membrane applicator. This is seen as a separate item on an estimator’s schedule of quantities and is often tagged out of membrane applicator tenders. There are many issues that can be avoided if a test method is considered early in the design and procurement phases of construction.
According to Masterspec Product Partner Thomas McLaughlin from ILD NZ, no one test method, Flood or Electronic, fits all membrane applications. For example, a concrete planter box is made to hold garden material and therefore a flood test is a suitable Quality Assuring test for this installation. However, a plywood roof over a living room is structurally engineered considering the loading of the structure itself and a maintenance loading calculation. This calculation in almost all cases will not accommodate for the deflection an additional temporary dead load a flood test will impose on the structure; therefore, an electronic test would be more appropriate.
Points to consider when specifying Flood Testing
- The structural capacity of the substrate to be reviewed by a licensed structural engineer to verify the loads associated with the flood test i.e you don't want the flood test to damage the roof or ceiling due to deflection
- Allow for this testing procedure in the Main Contractors construction programme.
- To record the Flood test, document the following criteria as per the ASTM Standard - you can download a copy of the Standard here
- Date and time at start of test interval
- Temperature, humidity, and weather
- Where are the points of observation, above and below the flood test area
- Monitor filling and record minimum and maximum depths of water in test area
- Document draw-down or added water during test period i.e. rain
- Observations made at the beginning of the test and at each four-hour time interval
- Location of leaks, if any can be defined
- Location and method of repairs if required and repeat test
- Duration of test, typically a minimum 24 hours
Points to consider when specifying Electronic Leak Testing
- What types of substrate is the membrane to be applied to;
- Concrete, Plywood or Warmroof Insulation board
- At what stage of construction should the test be specified to be undertaken
Electronic Leak Detection
When the electric field on the membrane surface encounters a breach, electricity travels from the roofing/waterproofing membrane surface through the breach to the grounding medium below. This completes the circuit, triggering the testing device to alert the technician that a breach has been detected. The technician then uses the test equipment to pinpoint the location of the breach.
To specify for electronic leak testing see 4481LD International Leak Detection System (available in Masterspec Standard, Basic, Landscapes and Structural & Civil).