Dear Barry,

I’m confused about foundation vents after reading your article emphasizing their importance. New studies, posted on the Internet at, state that foundation vents allow moist air to enter the crawlspace, causing condensation, fungus infection of the wood floor structure, and mold growth on sub-area surfaces. You say foundation vents prevent these conditions. They say the vents cause them. Who’s right? –Kevin

Dear Kevin,

Having reviewed that Web site and the studies in question, I find that they conflict with common sense and the experiential knowledge of countless field professionals. Excess moisture in a crawlspace does not enter through vent openings. The primary water source is the soil itself. It is wetness due to ground water runoff, on or below the surface, from natural springs or over-watering of nearby landscaping. The way to prevent water intrusion into a crawlspace is by improving site drainage conditions to prevent wetness of the soil from migrating beneath the building.

When ground wetness occurs below a building, it does what water tends to do under normal atmospheric conditions: It evaporates. When evaporation takes place in an enclosed space (e.g. an un-vented crawlspace), the humidity of the air increases. The problem with humid air beneath a building is that it condenses on whatever cold surfaces are available (such as wood framing, subfloor, insulation, steel hardware, etc.). When these surfaces remain wet for prolonged periods, natural consequences transpire: Hardware begins to rust, fungus and mold begin to grow, and dry rot eventually happens. The common means by which these conditions and consequences are avoided and eliminated is basic ventilation. In most cases, this is achieved by means of passive airflow, with simple screened vent openings at opposing sides of the building. Wherever passive ventilation is not adequate, mechanical ventilation may be added.

Any home inspector, pest control operator, drainage contractor, or mold inspector can tell you that eliminating these vents promotes condensation on the exposed building surfaces, with consequential damage in many cases. We see it routinely, wherever vents are missing or have been blocked. When vents are provided on one side of a building but not on the other, we typically find condensation and damage on the un-vented side. When homeowners add subfloor insulation and inadvertently block the vents, condensation and fungus damage often occur.

Whoever conducted that contradictory study should get out of the office or laboratory and crawl under a few thousand homes.

Dear Barry,

I’m writing this in reference to a local real estate agent who routinely recommends her husband to do home inspections for her clients. How can an agent recommend family members? Isn’t this a conflict of interest? Is it even legal? –Robert

Dear Robert,

It is clearly unethical for an agent to recommend a spouse as a home inspector. Whether it is illegal is a question that would vary according to the laws of individual states. Of the two agents I know whose husbands are home inspectors, both recommend other inspectors, rather than engaging in this questionable practice.

If you need a home inspector, do your own research before hiring anyone. Look for someone who has many years of experience and who is known among the local agents as “very thorough.” Call a few real estate offices and ask who is the most qualified inspector in the area.

To write to Barry Stone, please visit him on the Web at

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