It seems like everybody thinks every crawl space should be encapsulated. That is absolutely not true. Very few crawl spaces have conditions where encapsulation is necessary. If sufficient air flow can be gained naturally, the air will stay fresher, healthier. If there is not sufficient passive air flow because of landscape, fencing, other buildings blocking air, etc., a foundation vent fan or two installed behind an open vent cover, blowing out, will pull air through the rest of the vents turning it into an active air flow. If you’re old like me you can remember your family placing a box fan in an open window blowing out and opening the rest of the windows in the home. Fresh air would be drawn through the home. (That was our air conditioner back in the day!) This works in the same way, is inexpensive and helps allot!
If you do go do far as to encapsulate, make sure it’s done correctly. Out of 100+ encapsulations I’ve inspected, I have seen only two encapsulations that were correct. TWO! This is a fairly new process and training or a license is not required. Anyone can do them, and they are, charging huge amounts to do them wrong! That is a huge problem! A system installed wrong can be dangerous to the occupants. Indoor air quality can be severely affected. Radon is also still an issue and this could enhance it. Installing radon remediation if you must encapsulate should be required.
To learn more about correctly encapsulating click on Encapsulation ASTM Standard.
Go to page 14 to begin with simple illustrations. Page down and you will see an easier to understand diagram illustrating the process. Please, if you do choose to do this, first, do your homework. This information in this standard provided is so important! Then, find a qualified installer and ASK QUESTIONS! Get them to explain exactly what they do. If they leave out a step, move on. Also, make sure they pull a permit as there is mechanical parts to an install that require permitting. Feel free to call me if you have any questions.