Technical Guidance to the Indoor airPLUS Construction Specifications
1. Moisture Control
Please see "How to Use This Guidance".
Sections 1.1 - 1.4
Water-Managed Site and Foundation
Sections 1.5 - 1.6
Water-Managed Wall Assemblies
Sections 1.7 - 1.10
Water-Managed Roof Assemblies
- 1.7 Direct Roof Water Away from House
- 1.8 Fully Flash Roof-Wall Intersections
- 1.9 Install Self-Sealing Bituminous Membrane
- 1.10 Install Self-Sealing Bituminous Membrane in Cold Climates
- BEST PRACTICE: Roofing Underlayment Upgrade
- BEST PRACTICE: Roof Drip-edge
- BEST PRACTICE: Wind Baffles - Attic Insulation
Sections 1.11 - 1.13
Sections 1.7 - 1.10: Water-Managed Roof Assemblies
Best Practice: Roof Drip-edge
Metal drip edge material should be installed at all exposed edges of the roof decking.
Detailed Illustrations: Best Practice Techniques
Drip-edge materials protect the edges of roof sheathing from water penetration due to driving rains; the material is bent in a form that channels water away from the roof edges, thus protecting rake and fascia boards. The drip-edge material that extends past the edge of the sheathing supports the outermost edges of the shingles, enabling them to drip water while providing structural support so the shingles last longer without splitting or cracking.
See figures in guidance 1.9 and 1.10. Always apply the first strip of metal drip edge at the eaves, directly attaching it to the wood sheathing. Then, cover the roof decking with peel-and-stick membrane or building paper. Next, attach the drip edges to the rake ends of the roof deck, allowing these drip edge strips to cover and hold down the outermost edges of the building paper or membrane. Drip edge strips have a horizontal leg that lies on the roof deck (or on top of the underlayment covering the roof deck) and a vertical leg that is bent down 90 degrees. When installing drip edge, space the vertical portion of the drip edge strips approximately 1/8 in. from the edge of the rake and fascia boards to allow water to drip freely from the drip-edge.
- Durability By Design, A Guide for Residential Builders and Designers, U.S. Department of Housing and Urban Development, Office of Policy Development and Research, Partnership for Advancing Technology in Housing, PATH, May, 2002. See www.huduser.org .
- Build a Better Home - Roofs, APA – The Engineered Wood Association, 2003. See www.apawood.org/