Georgia-Pacific just released a new white paper detailing the results of recent testing on their DensElement sheathing. DensElement is a hybrid sheathing panel that is intended to function as both air and water barrier as well as sheathing when installed per the manufacturer’s guidelines. The testing was performed by Intertek.
The press release on Building Enclosure states:
To simulate severe wind-driven rainy weather conditions, three separate wall assemblies utilizing DensElement Barrier System as the primary water-resistive barrier (WRB) were subjected to high volumes of water on the surface of the wall while simultaneously applying uniform static pressure to the opposite side of the wall for a specified period of time. In all three separate high-pressure water penetration tests, DensElement Barrier System proved successful in withstanding bulk water with a variety of rainscreen attachment systems.
Building Enclosure
Reading more carefully, the white paper itself elaborates on the testing procedure and the results. The panels were tested with various cladding attachment clips/brackets per ASTM E331 at static air pressure differences up to 900 Pa (just under 19 psf) for up to 30 minutes. In all but one case the test panels passed the test without leakage. In the one that leaked the brackets were intentionally installed in a way that did not comply with the manufacturer’s instructions in order to maintain consistency with other test specimens.
The white paper summarizes the results in this way:
These findings show that, in conjunction with the tested cladding attachment systems, DensElement Barrier System provides excellent resistance against bulk water from wind-driven rain. When properly installed, DensElement Barrier System is a proven reliable WRB-AB across a variety of wall assembly designs, whereas misapplication and failure to properly install can result in unwanted leaks, water damage, and air flow.
Evaluating the Effectiveness of the DensElement Barrier System as the Primary WRB in Rainscreen Assemblies
The paper’s summary also notes the added redundancy provided in a real-world scenario where the building cladding is in place:
Unlike in this test situation, actual building scenarios should also include a cladding installed over the subframe, adding to the building envelope’s ability to deflect wind-driven rain. In such rainscreen assemblies, the drainage space that these subframes creates between the sheathing and cladding helps to promote drainage and further mitigate the risks of bulk water entering the interior side of the wall assembly during a storm.
Evaluating the Effectiveness of the DensElement Barrier System as the Primary WRB in Rainscreen Assemblies
While it’s certainly wise to consider the source of this information (the manufacturer of the panel itself) it’s still valuable information for designers considering materials to specify in their projects or for consultants evaluating installed materials. In the absence of peer reviewed and truly 3rd party evaluations this kind of data is much better than anecdotes and speculation.