Decay Fungi
Brown rot fungi feed on the wood’s cellulose, a component of the wood’s cell wall leaving a brown residue of lignin, the substance which holds the cells together. Infested wood may be greatly weakened, even before decay can be seen. Advanced infestation of brown rot is evidence by wood more brown in color than normal, tending to crack across the grain.

Water Decay Fungi
Most decay fungi are unable to conduct water very far and can only attack moist wood. However, PORIA INCRASSATE, called dry rot or the water conducting fungus, will decay wood which would not be attacked by typical decay fungi. Poria infested wood is often mistakenly identified as subterranean termite damage. Typically, infestation of Poria begins in dirt filled porches, damp crawl spaces and basements where wood is in contact with the soil. At first, yellowish mycelial fans grow over the surface of joists and sub-floors, or in protected areas. Irregular root like rhizomorphs may appear on foundations, framing, sub flooring and other moist areas. Once established, it can quickly spread through a building and destroy large areas of flooring and walls in as little as a year or two.

It is unbelievable how many homes are damaged or literally being eaten up from wood destroying fungus. The culprit is moisture. It amazes me to find so many homeowners that I have met that have never even been under their home or paid a professional to go under the home and inspect their investment. What’s even harder to believe is that some homeowners are told of a problem or damage and it is either put on the back burner or totally forgotten about. Many homeowners tell me that they hate to spend money on something they cannot see.

If you have a termite inspection once a year done by a reputable termite company think about this, most of the pest control companies send out hourly employees with little or no knowledge of mold, wood destroying fungus and moisture. Sure most can identify these problems but have no idea how to treat or cure not only the mold and mildew but the cause. They are in the business to detect and kill termites and other wood destroying insects. Termite companies kill bugs, and most are not certified mold remediators and they certainly do not know how to properly produce a healthy dry crawl space area. Now don’t get me wrong. There are a lot of experienced and competent termite companies out there that do know their limits and do not give the wrong advice on how to treat it. I have heard of everything from installing gutters, installing fans to remove the moisture or to circulate the air, additional foundation vents installed in the garage walls or tunneling through the front porch through the brick veneer, adding sand under crawl space, and of course the installation or replacement of the vapor barrier. And how convenient; they all claim to do these services.
THEY DON’T WORK.

Think about it. Yes gutters do divert water from the foundation and I would also suggest them if you do not have proper grade around the perimeter of your home. Installing sand under the home on top of water puddles is like putting a dry sponge in a glass of water, it’s still there but in a different state. Installation of fans (replacing moist humid air with moist humid air) does not make sense either. Same goes for spending thousands of dollars to install vents through your foundation out through the front porch or even better yet into your garage. This is just an invitation for the smell and odor of damp, musty, moldy earth not to mention snakes and vermin to enter your garage area. Vapor barriers do help but must be installed correctly and only if you have mild ground moisture. Only 80- 90% of the ground surface should be covered if you do not have a moisture control system under the home removing excess moisture otherwise you are defeating the purpose. Remember, there are thousands of homes that do not have drainage problems that have sick crawl spaces due to high humidity.
It’s an Air Humidity problem, not a water problem

Your home is one of the largest investments that you will make in your life, please go to the links below, do some interesting reading and then you can make educated decisions.

Research from Industry Experts:
Unvented Crawlspaces (PDF) - This brief guide published by Dominion Power Company shows how crawl spaces perform better if properly sealed.

Building Science Corporation - The problems with vented crawl spaces is discussed in this “Top Ten Dumbest Things To Do In The South"

RLC Engineering Research - This paper describes the fallacies of the traditional vented crawl space.

Advanced Energy Corporation - Advanced non profit research organization has lead the way in proving the success of sealed crawl spaces which was done in North Carolina.