When Residential or Commercial buildings experience Water Damage (i.e. from a pipe burst, wind damaged roofs, a washing machine hose, refrigerator ice maker supply lines, etc.), “many people” valiantly attempt to address these types of problems themselves. 

Most of the time, these events are 100% covered (less deductable) by the owner’s P&C insurance policy.  Almost always, “DIY solutions" lead to improper drying techniques, due to a misunderstanding of the scope of such damage, which will cause secondary property damage from mold.  Please remember that PuroClean Property Rescuers NC is the firm to call in any water loss situation…

Regardless, flowing water from such events will always follow the path of least resistance, rushing downward through wall partitions and wood flooring/subflooring.  This water will eventually typically end up in the Crawlspace.

NC Building code requires builders to properly cover crawlspace dirt floors with heavy gauge polyethylene, which does an excellent job at keeping evaporating water from rising and coating the wood structures above with moisture which should eliminate fungal microbial growth (mold) and eventual decay.

The problems that arise from water damage events occurring above a crawlspace that is lined with poly vapor barrier exposes the “downside” of having a vapor barrier.  Such water collects on top of the poly, creating “pools” of water over the poly and under the wood structures as well as the sponge-like insulation above.  These pools left unattended will create rot-related problems associated with mold and while “white mold” (referenced photo) may not be a health risk; there is no guaranty that the mold that may grow there may fall into the general category of “toxic mold”…

We received this amazing picture showing white mold growing on wood in a crawlspace from one of our site visitors.  We wish to thank them for giving us permission to use the picture for training people about mold.  For confidentiality reasons we will not mention their names here.  The picture was taken from the crawlspace of a new building which has a wood basement floor and wooden joists with a crawlspace under.  The crawlspace was lined with poly vapor barrier and gravel poured over the poly to hold it in place. Unfortunately, prior to roofing, it rained and the water collected on top of the poly, creating a “pool” of water over the poly/gravel and under the wood floor.

The pool of water sat in this confined space with no air movement and no drainage until power was connected and a pump could be placed in the sump to pump it out. In approximately 8 – 10 weeks, the white mold began to grow. When it was first noticed, it varied in length from 1/4″ in length to 1″ and covered approx. 25% of the wood joists. Within 2 weeks, it had grown from 1 inch to 4 inches in length (approx. 4 times!).

What could the white mold be?

From the picture, it’s difficult to tell for sure. However, there are a number of common wood-rotting fungi that infest damp or water-damaged wood. We shall discuss this in detail in the next post.

Could this mold be a health hazard?

Probably not...  However, if it’s not completely removed, it could destroy the wooden joists completely thus compromising the structural integrity of the basement floor.