December 2008


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Richard Faesy <[log in to unmask]>
Reply To:
VGBN Discussion <[log in to unmask]>, Richard Faesy <[log in to unmask]>
Fri, 12 Dec 2008 17:36:59 -0500
text/plain (76 lines)
An unvented space heater like a salamander dumps all of it's products of combustion into the space in which it is located.  This results in approximately 1 gallon of water vapor produced for every gallon of propane or kerosene burned, assuming complete combustion (see  (If out of tune, CO is also dumped into the space).  This moisture ends up somewhere in the building structure, like the insulation, or condenses out when in contact with cold surfaces, like windows or plastic sheeting.  The best approach for temporary space heat is to use something like a condensing gas furnace without attached ductwork and vent the flue gasses to outside.

Richard Faesy
Vermont Energy Investment Corp.
14 School Street
Bristol, Vermont  05443
P: 802-453-5100 x19
F: 802-453-5001
C: 802-355-9153

-----Original Message-----
From: VGBN Discussion [mailto:[log in to unmask]] On Behalf Of Tim Yandow
Sent: Thursday, December 11, 2008 8:24 PM
To: [log in to unmask]
Subject: Re: [VGBNTALK] damp cellulose

Can someone explain to me how a Salamander can exacerbate moisture issues
during dry out? Is this a problem with dense pack as well? What would be a
better way to provide heat for drywall and painting after insulation
installation than space heaters?
Tim Yandow

>            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:                                  --- On Thu,
> 12/11/08, William C Badger AIA  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.