Drains, slopes and ponding: getting the water off a coated deck
After rain, the transit parking deck has water near a drain and another patch behind a wheel stop. The project manager is asked whether a thicker coating would solve both areas. There is no located survey or assessment to show which condition needs what decision.
Treat the observations as questions about the deck’s levels, drainage and interfaces before proposing a coating correction. The cited application instructions include system-specific drainage and drain-edge preparation. They do not authorize altering this structure or adding drains from a photograph. Document what is visible, then obtain the responsible assessment and compatible approved detail.
Give the drainage review useful evidence
- Locate the observed water. Mark the area on the deck plan and record the observation time, recent conditions and relevant obstructions. Take an overall view and a drain-interface view where safely accessible. Avoid describing an unexplained wet patch as a failed membrane or assigning its source immediately.
- Check available design information. Gather current drainage, slab and coating details, relevant finished levels and previous changes. Identify missing references. A low point on a sketch does not establish which trade should change it or whether an existing interface matches its design.
- Arrange the appropriate assessment. Ask the responsible designer and qualified survey or technical team what observations or measurements are required. Coordinate safe access and any approved testing. Do not introduce water, plug drains or direct grinding merely to create clearer evidence.
- Obtain the correction and its limits. Retain the approved decision for each located concern, including compatibility with the substrate and coating assembly. Separate level work, drainage work and membrane details. An instruction to investigate a low area is not approval for a thicker finish or structural cutting.
- Coordinate interface ownership. Confirm the sequence and responsible trades for the drain body, receiving surfaces, coating termination and adjoining work. Identify the required review stage before covering. Keep drainage component identification visible so a finish photograph can be traced to the actual interface.
- Retain verification and remaining exceptions. Link the completed approved work with its required check and assessed disposition. Record limitations or accepted conditions explicitly through the authorized process. Give the owner the located history instead of claiming that the whole deck will never hold water.
Checklist
The drainage decision package
- Located observations and conditions.
- Current slab, drainage and assembly references.
- Required qualified assessment.
- Approved correction and compatibility decisions.
- Named drain-interface responsibilities.
- Verification record and visible limitations.
Check your understanding
A ponded area appears close to a drain. Does that prove the drain or coating caused it?
_17_-_Third_Floor.jpg){kind=link}