Definition
A material that limits moisture from passing through walls or ceilings into the insulation and structure. Proper placement keeps insulation dry and prevents mold and rot.
Why this term matters for homeowners
Home-performance terms map to attic ventilation, insulation, energy bills, and how the systems above your ceiling protect the roof's lifespan.
- Use this term to ask better follow-up questions during estimates.
- Look for this language in Learn and Evaluate guides to connect definition to decisions.
- Confirm how this applies to your specific roof age, pitch, and home layout.
Related pages
Category: Home Performance