Re: Urgent Question [attic and crawl space ventilation]

[Guest guest]

Jeannene,

Unless you are located in an area where the relative humidity rarely gets

over 60%, ventilating your crawl space is a MISTAKE. Some building codes now

allow for unventilated crawl spaces (most will follow soon).

You must go to <www.crawlspaces.org> to see the research that shows that

traditional ventilation with outdoor air CAUSES mold problems. If you bring

in lots of humid, outdoor air, you will end up doing another mold clean up.

The most sensible thing to do with the crawl space is to dehumidify it (with

a ThermaStor Advance if it's a big space; in any case, use a condensate pump

to get rid of the water), and make the space airtight to the house and

exterior. (Or, as described at the website, you can have a small amount of

dehumidified fresh air brought in if you like.)

DO NOT include the crawl space in the HVAC system as recommended by the

website. The idea of a crawl space " conditioned " by anything other than a

dehumidifier is very risky.

Also, be very careful about the ridge and soffit vents that you use. Most

ridge vents are either useless (because they are blocked by mesh) or the

roof sheathing is not cut away when the vent is installed.

Circular soffit vents are useless because they have too little free area and

get completely clogged the first time the soffit is painted. Use continuous

strip venting.

Believe it or not, keeping house air out of the attic is much more important

than the amount of ventilation. You can easily defeat any amount of

ventilation and end up with an attic full of mold by just having a warped,

pull-down stairs that is leaky or a bathroom fan that is vented into the

attic. Check the attic carefully for air-leakage sources (around pipe, duct,

wire chases) and seal them. Gasket the pull-down stairs.

C. May, M.A., CIAQP

>Re: Urgent Question

>Posted by: " JALD111@... " JALD111@... jald111

>Date: Sun Jan 13, 2008 7:20 pm ((PST))

>......We have hopefully addressed the ROOT of the problem in both areas by

>correcting the problem in inadequate ventilation and installing both ridge

>vents on the roof with air ventilation in the eaves and creating a >ventilation

system in the crawl space as well......

>Jeannene

[Guest guest]

Where do you live? What is the average humidity, temperature, rainfall,

snowfall, pressure ranges? What is your altitude and basic geographical

habitat?