NASCLA Accredited Commercial General ContractorConcreteMedium
A project requires a concrete slab on grade to be poured over a vapor barrier. The subgrade has been properly compacted and prepared. Prior to placing the reinforcement and concrete, what is the critical step to ensure the vapor barrier remains effective and undamaged during the subsequent operations?
- AHeating the vapor barrier to improve its elasticity.
- BApplying a curing compound directly to the vapor barrier.
- CSprinkling water on the vapor barrier to keep it moist.
- DPlacing a protective layer of sand or fine aggregate over the vapor barrier.
Show answer & explanationAnswer & explanation
Correct answer: D. Placing a protective layer of sand or fine aggregate over the vapor barrier.
Placing a protective layer of sand or fine aggregate over the vapor barrier prevents punctures and damage from foot traffic, rebar placement, and concrete pouring, ensuring its integrity and effectiveness.
Why the other options are wrong
- A. Heating the vapor barrier is not a standard practice and could potentially damage the material, reducing its effectiveness.
- B. Curing compounds are for concrete, not vapor barriers, and would not protect against physical damage.
- C. Sprinkling water on the vapor barrier is unnecessary and does not protect it from physical damage.
Vapor Barrier Protection
Measures taken to prevent damage to a vapor barrier during construction activities.
- Essential for maintaining barrier integrity.
- Typically involves a protective layer.
- Prevents moisture migration into the slab.
Memory trick: Subgrade Smooth, Barrier Safe, Rebar Ready, Pour Perfect.