We all know that crawl spaces are often overlooked or not given much attention by homeowners. However, moisture in crawl spaces can have serious negative effects on the home’s structure as well as the health of the family that lives there.

Moisture in crawl spaces is a common problem that can contribute to rotted sills and rim joists, mold problems, and insect infestation if not controlled. It has also been associated with health issues that can accompany mold, mildew, and other problem organisms.

There are a number of steps that can be taken to reduce moisture levels in crawl spaces. Some items to consider are as follows:

• Grading – Ideally, the crawl space grade should be higher than the outside surface grade, and grading around the home’s perimeter should always slope away from the foundation
• Ventilation – Especially in colder climates, crawl spaces should be ventilated to the outdoors as well
• Vapor barriers – depending on the climate, using a vapor barrier on crawl space floors will aid in controlling excess moisture
• Vent wells – Vent wells should be used if foundation vents to the crawlspace are fully or partially below grade

There has been considerable debate in many areas about the benefits and disadvantages of vented vs. closed crawl spaces. Some building codes, particularly in warm, humid climates, have been moving toward requiring closed spaces. Research continues on this topic at both local and national levels.