Here in northern Nevada the argumant is always whether or not to open or close the vents. Most get closed and stay that way forever or until an HI or pest guy comes along.

I usually tell them to open the vents always to allow for ventilation. Many of our crawlspaces are damp.

Recently a company in Carson City has been selling the "Clean Space Crawlspace System". This system does require closing and sealing of all the vents as well as any other gaps or holes to the exterior. A heavy guage vinyl moisture barrier is installed and sealed at the seams and to the perimeter foundation wall. A sump pump with battery back-up is installed as is an automatic fan system. I hear its really spendy to install.

I've only seen one in the Reno area and it was a pleasure to crawl around in - really clean. The home above was a disaster but thats another tale.

Jonathan

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Jonathan M. Cartwright
Newberry Inspections, LLC