Monitoring real life assemblies is the best proof of performance. This is how we know Pro Clima products make construction as safe as possible.
As we describe in the presentation High Performance Gets Real, a vented roof is generally preferred because of the added drying potential it can provide. However, space constraints can make an un-vented roof necessary. In this case, the builder also preferred the robustness of dense pack cellulose with the INTELLO Plus airtight smart vapor retarder membrane.
Moisture sensors were placed at the inside of the exterior ZIP/OSB sheathing and at the I-joist cord just above the inboard INTELLO. The sensors recorded Wood Moisture Equivalent percentage (%WME), or Moisture percentage (M%).
As with most residential projects, the assembly contained primarily wood-based construction materials. The cellulose and wood moisture contents started at elevated levels because of how they were delivered and installed.
But no harm was done. The collected data, provided by ECOCOR, shows that the roof assembly dried out within the first summer. At the exterior sheathing ZIP/OSB sheathing (orange data line), moisture levels never exceeded our recommended safety buffer limit of 15M%.
The interior data points (blue line) also shows moisture levels trending downward each year – indicating how effectively INTELLO Plus builds drying reserves through inward drying.
See more of our moisture recommendations in Drive Safe, Build Safe.
Chris Corson, and Kohta Ueno of Building Science Corporation, presented (in part) on this assembly at the NESEA conference in Boston, which you can find here on the NESEA site.
Related Blog Posts:
- JLC Reports on Success of Foam-Free Unvented Flat Roof Assembly
- The Ten Golden Rules for Foam-Free Flat Roofs
- The 8 Golden Rules for Foam-Free Unvented Asphalt Shingled Roofs
- 475 Presents: High Performance Gets Real
- Drive Safe, Build Safe
- Yes, Unvented Roof Assemblies Can Be Insulated With Fiberglass; A WUFI Post
- New Mold Growth Index and Safe Double-Stud Walls: WUFI Pro Shows INTELLO Plus is Key
- INTELLO & DB+ Approved by DIBt for Use in Unvented Hot Roof Assemblies