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Build a Better Home: Moisture-Resistant Roof Construction

Build A Better Home

Preventing moisture from getting trapped inside the building envelope is key to constructing long-lasting homes that stay dry and comfortable. Both the overall design of the roof and the finishing materials are important factors in designing a building to withstand moisture penetration. 

This publication is designed for: architects, builders, homeowners, designers, contractors

Moisture is introduced into homes in three primary ways: bulk water from water via leakage, infiltration through building materials and vapor transmission from interior and exterior sources. The best treatment for moisture build-up is prevention by employing good construction practices and maintaining proper ventilation.

This publication provides information about how water can get into homes, as well as descriptions and diagrams of roof designs that can prevent moisture intrusion.

Key sections include:

  • Designing roofs to prevent moisture infiltration

  • Low-slope and pitched roofs

  • Roof sheathing

  • Roofing underlayment

  • Finished roofing materials

  • Roof intersections

  • Flashing details

  • Ventilation

  • Ice dams

Published by APA — The Engineered Wood Association.

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