Question: I have an 8 year old home in BC’s Gulf Islands. On a recent trip into my crawlspace noticed some mold growth or fungus on the underside of the vapor barrier that is applied over the earth in the crawlspace. There is no sign of any mold growth elsewhere. The crawlspace has four vents that have been opened all summer, and I see no moisture in the crawlspace except some water droplets probably condensation under the vapor barrier. The concrete walls of the foundation are insulated and the crawlspace is correctly vented. Should I be concerned, should I close the vent’s over winter, or is there anything else I should do to stop this.
Answer: If you only noticed minor mold growth on the underside of the vapor barrier, you don’t have to be concerned. However, I would suggest you continue monitoring the entire crawlspace and if you see mold growing on wood, it’s an indication that the crawlspace is damp enough to support mold growth. In that case I would recommend that you consult a professional experienced in building foundation to determine the cause of dampness and how it may be rectified. As long as the the crawlspace is damp there will be mold growth.