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Re: prevention methods for indoor mold growth


I've fogotten so much, but still know a little bit on this one.  This is
due in part to a great background on indoor air quality, energy efficient
building, and living in arctic and rainforest parts of the US.

Would just tell you that there is no easy answer - hey, an engineer's gotta
live, too.  The point of moisture formation as a contributor to mold growth
is due to both air pressure and thermal factors, and a good designer is
cognizant of both.  Whether the strategy should be to prohibit (how
successfully can this be done?)  moisture migration from a warm moist
environment to a cooler condensing environment, or to try to ensure that
the cooler condensing environment is external to the living and air
handling spaces is occassionally an energetic topic of discussion. When I
lived in Juneau, the unplanned additional insulation in the bedroom closet
of some luggage against the wall was sufficient to move the condensing
plane into the closet instead of inside the wall.  Nails and drywall screws
would similarly be initiating points for moisture and mold - many older,
more poorly insulated homes had this happen.

So by recognizing the flow of moisture, and what enhances or restricts it,
you have a good place to start in deteriming your actions.  I haven't seen
a really well sealed building, except in the most fastidious cases of a
homeowner doing their own construction ...

A second strategy would be to reduce the unnecessary introduction of
moisture into the building envelope.  I think the clothes dryer vent
divertors are still on the market - a way to retain the heat in the house,
certainly - but a huge source of moisture. Cooking with lids off, excersize
rooms, stem baths, etc.  Use fans in high-humidity rooms.  How important
the additional moisture is depends on location, home construction and other
factors...  I remember the pan of water onGrandpa's pot-belly stove, to add
moisture to the mid-winter air...  But that was a drafty old house..

And a third strategy would be to routinely clean - remove the mold from the
surface.  But really - how often would you check behind your suitcase in
the upstairs closet??

But there are also mold issues in warm high-humidity areas such as

As for good sources of information, the Canucks were leaders in this
decades ago, along with builders/engineers in some cold-weather states such
as Minnesota and Alaska.

I've always thought ASHRAE has good documentation of these things (go to
ASHRAE.org and search for mold), but if you'd like, you can go to
Peakstoprairies.org - they have a green construction topic hub with good
contacts for such things. and they are working on a "homes across
america"program that will touch on this as well, i think.

i'd suggest defining the problem a little better - what type of
construction, use of the facility, location, etc would be useful in better
answering your question.

BTW, EPA has a decent introductory page on the topic:



Richard Yoder, PE
Director, P2ric.org
1313 Farnam St.   Ste. 230
Omaha, NE  68182

fax: 402-595-2385

                    Sent by:                 To:     p2tech@great-lakes.net                                             
                    owner-p2tech@great       cc:                                                                        
                    -lakes.net               Subject:     prevention methods for indoor mold growth                     
                    03/03/02 09:27 AM                                                                                   
                    Please respond to                                                                                   

In the construction phase, are there specific tactics/methods of preventing
mold growth in walls?

i assume water-tightness is first/foremost.  heard something about visquene
as an added  vapor barrier between insulation and inside wall?

THANKS in advance.