Could mold make my house worthless? It might take a Herculean effort to salvage it, but not likely to be a total loss:
A family occupying a house in one of the
Southern California beach cities
contacted my company complaining of respiratory and other symptoms often
associated with exposure to microbial toxins and allergens. Our inspection revealed mold growth inside
walls and ceilings in a numerous locations.
These mold growth sites were apparently fostered by rain leaks due to
construction defects. The siding on one
side of the house was visibly rippled because of poor construction.
The homeowners ended up having to sell the house for a loss and brought a lawsuit against the original owner of the house who had overseen the construction and had not disclosed conditions that he should have been aware of. We also discovered that members of the original owner’s family had been ill with chronic respiratory problems at the time of the sale. The basis of the lawsuit was non-disclosure of some of the more obvious construction defects. Once the family moved out of the house most of their symptoms reduced or simply disappeared.
About two years later I got a call from the new owner of the house. He was in the process of rebuilding so he could put in on the market. He had removed all fixtures and drywall to the extent that the house was taken down to the framing materials. His concern at the time he contacted our company was that there should be no mold growth sites on the framing materials that would become sealed up inside the walls. His concern was justified. Black mold was visible in many locations on the framing members. Black mold growth on wooden materials is not unusual. Virtually every house I have ever inspected has such mold. At times I take a sample just to ensure it is what I think it is. When the house is built the materials used often have growth of what is referred to as common lumberyard mold (Ceratocystis-Ophiostoma group). The presence of such mold is a given in essentially any house. As with most molds, it is assumed that sufficient exposure to lumberyard mold can elicit allergic responses in some individuals. The effect of exposure to these mold types is not well studied but persons most likely to be found allergic are those who routinely work with lumber such as carpenters and lumberyard workers.
But I digress... I took samples from framing materials in locations where I recalled there had been moisture problems resulting in mold growth. The purpose of the sampling was to determine if the growth was lumberyard mold or growth of potentially more harmful molds resulting from previous water incursion into the walls. In every location sampled the mold was found to be other than lumberyard mold. My recommendation was to have the entire house, i.e. the portions remaining, sandblasted to remove the mold growth from the framing members. There was some initial resistance on doing this based on the expected cost. After determining the labor costs of trying to achieve the same thing manually, the sandblasting was done. Of course, appropriate personal protective equipment was required for personnel doing the sandblasting. Inspection showed no visible mold growth and re-testing showed no remaining mold growth in the locations tested so the house was ready for rebuild.
To reiterate what has been previously mentioned, with sufficient exposure lumberyard mold, like virtually all molds, is potentially allergenic. It appears from the available information, however, that few people are exposed to the degree necessary to develop an allergy. I doubt that a person can buy a currently built house without such mold on the timbers.