Proper Preparation Can Prevent Mildew GrowthJuly 2nd 2014
Q: We had some of our summer patio furniture stored in the crawl space. We have brought it out and were surprised to find a strong musty odour, as well as some mildew on some pieces. What can we do to prevent this happening again?
A: Crawl spaces are not designed to be a storage or living area, but as areas for electrical, plumbing and heating systems. I am not saying you should not use your crawl space for storage, but there are a few things you should do before using the area for stored items.
If the home has a dirt floor in the crawl space, cover the area with six ml plastic poly and seal around the footings and pier pads with an acoustical adhesive. Newer homes will likely have a rough trowelled concrete skin coat over the poly, giving a solid surface to crawl around on. In any case, before any storage is put in place, lay down strips of treated lumber on the floor surface. Place your boxes, etc. on the wood strips, allowing air to move around the stored items eliminating direct contact with the floor surface.
Musty odours and white powder on concrete surfaces in the crawl space indicates high levels of moisture. The concrete should be sealed with an aqua sealer. Crawl space vents should be kept open in summer and closed in winter. Moisture can be vented to the outside by installing a mechanical crawl space ventilation system controlled by a dehumidistat. This can be set at the required relative humidity of 50 to 60 per cent.