Case 6
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- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Good Practices
When using liquid-applied membrane:
Coats of fluid bitumen are applied on the roof surfaces with the use of brushes or rollers. To do this:
- Three coats are applied till a minimum thickness of 1.2mm.
- After application of the first coat, the second coat has to be applied in perpendicular direction to the first coat.
- The second coat must be applied while the first coat is still green but sufficiently set so that it is not drawn off while applying the second coat. Thus, a strong bonding between the layers can be ensured.
- A membrane up-turn of 300mm must be done whenever there are areas that need to be upturned (e.g. parapet wall and pipes protrusion).
- The finished membrane is left to cure for a minimum of 24 hours prior to water ponding test.
- A sample board is often used to show client the finished thickness of the applied-liquid membrane. This will allow the client to have a cross sectional view of the membrane thickness.