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Moisture Control in Low Slope Roofs

Technical Note

Low-slope panelized wood roof systems in commercial and industrial buildings face unique moisture challenges that can lead to fastener corrosion, condensation dripping, and wood decay. Unlike pitched residential roofs that rely on ventilation and vapor barriers, these non-ventilated systems require specialized knowledge to prevent moisture accumulation while maintaining energy efficiency.

This publication is designed for: architects, engineers, builders, designers

The publication provides comprehensive guidance on moisture sources, condensation mechanics, and the self-drying roof concept. It explains how increased insulation affects condensation risk and offers practical solutions for balancing moisture control with thermal performance.

Key sections include:

  • Moisture sources in wood construction

  • Moisture from condensation

  • Condensation zones

  • Accumulated moisture

  • Use of vapor retarders

  • Minimizing moisture loads during design/specification, construction and service life

Published by APA — The Engineered Wood Association.

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