The borates seemed to work fine in the cellulose - there was no mold in the it. Moisture had condensed on the back of the Typar. Too much moisture in the application, extra moisture introduced by space heaters, interior walls left open too long meaning to help it dry, winter conditions promoting condensation, Typar creating issues? Any or all are options, but no one seems to be able to pinpoint one cause or whether it was a combination of all. NuWool was the brand and I understand it is the good stuff. The installation installer has since sold his business and vanished. The builder was one of the best in the business. Walls were left open for several months (now one reputable local installer is saying to close the walls in within a week). Salamanders were used because no one said not to. Probably a combination of a number of things except poor construction. Lots of people chipped in to help fix the problem, but it still cost the builder. Fortunately the homeowner was understanding, but until it is established exactly why it happened it is an experiment I don't intend to repeat.

Bill

Robert Riversong wrote:

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--- On Thu, 12/11/08, William C Badger AIA <[log in to unmask]> wrote: Interesting material. Has anyone in the group tried it and does anyone locally install it? We tried damp applied cellulose in a new house a couple of years ago with disastrous results. Black mold grew on the outside of the plywood sheathing and the back side of the Typar house wrap. The siding had to be stripped off and things dried out. A series of unusual circumstances that created a perfect storm?   The mold on your plywood sheathing may have been encouraged by poor installation practice or too quick a close-in of the walls, but likely had other contributing factors.   Kiln-dried lumber is milled at 19% moisture content by weight and it takes a new house a full year to completely dry to a stable level. Modern cellulose installation techniques require very little added water, and the walls should always be left open from 1 to 3 days following application.   Running salamander-type temporary construction heaters only puts more moisture into the indoor environment. Cellulose has been successfully installed in northern climates without a vapor barrier (as long as there is good air sealing), and applying a plastic vapor barrier and closing in the wall before dry-out will almost certainly create a mold problem.   The brand of cellulose, also, makes a big difference. Only those, like National Fiber, who use EPA-certified fungicides can guarantee no mold problems.   If wall plate penetrations in the top and bottom plates are not properly sealed, this could create a significant source of moisture in the wall cavities.   My guess is that you had a "perfect storm" caused perhaps by poor quality materials, poor installation technique, and inappropriate construction practices. Don't blame the cellulose - there is no better insulation on the market.