basement(or other)humidity level?

[Guest guest]

Just so we get this right, What should the humidity % be in a basement or other

rooms of a house? thx, Felice

[Guest guest]

There is an excellent pamphlet by the EPA that goes into length on

this subject, " Mold Remediation in Schools and Commercial Buildings " .

They go into a detailed explanation of how to track down moisture

issues, dew points, vapor barriers, etc. I don't think that its

*simply* a matter of humidity so much as you need to examine the

entire picture.

People often say '50% relative humidity' because its been shown that

many molds can grow at humidity levels not that far above that *once

they get established at higher humidity levels*.. The humidity at or

near a wall is usually substantially higher than the humidity at the

middle of a space, etc.. So the idea is to give yourself a safety

margin if its possible and mold has already been shown to be a problem

in that space.. Thats what I think they mean when they say " 50% " . They

mean this is a good target when people use dehumidifiers and fans to

achieve it.. (in climate controlled environments in humid climates..)

Either that or ensure that the basement and any other problem areas

are sealed off from your space.. outside the living space

air-ciirculation wise.... i.e. *outside* the building envelope.. One

or the other.. or both..

Most molds that produce mycotoxins are the most toxic at much higher

humidity levels.. But if you have a hidden leak or have had one or

flooding in the past, humidity inside your walls could be very high..

even much later, somewhere, but that spot might be completely hidden

to all unless you start breaking into walls..

i was trying to give my shot at this and keep it simple but I've made

a mess of it. Really, you should read the EPA's pamphlet. Its the

definitive analysis of this subject.