What must be constructed if the threshold of a shower is less than 2 inches high during a liner test?

In situations where the threshold of a shower is less than 2 inches high during a liner test, a temporary threshold must be constructed to ensure that water does not escape the shower area while the liner's integrity is being tested. The purpose of this temporary threshold is to prevent water leakage, thereby allowing for an accurate assessment of the shower liner's performance and effectiveness in containing water. This solution is crucial for maintaining compliance with plumbing codes that safeguard against water damage and ensure proper drainage.

Other options do not meet the specific needs during the liner test. A permanent barrier would not be appropriate as the test typically does not involve long-term installation modifications at this stage. A sloped ramp may not adequately contain water, leading to potential leakage, which directly contradicts the purpose of the liner test. An adjustable board might still not effectively contain the water as needed, as it may not provide a sufficient seal during the testing process, rendering it ineffective for this specific requirement. Therefore, the construction of a temporary threshold is the correct and practical solution in this scenario.