Easy fix for Basement Humidity & potential mold issues

[Pat L.]

I read about this idea on a self help web blog some time ago but can't remember where so hopefully it won't be a copyright issue.

We have several rubble/hand dug very damp basements so I tried it in what I consider the worst case. We had a dehumidifier running 24/7 & its proved to be a simple cost effective solution using old ducting & an old ductwork fan. Here is the writeup....

" A dehumidifier alternative

Having given up on the questionable reliability and durability of dehumidifiers for our basement, I decided to try a low-tech, low-cost alternative to deal with summer humidity problems. Opening the basement windows provided some airflow but did not reduce humidity at floor level. 

A better solution was using a 6-in.-dia. axial fan. The fan moves 239 cfm of air while drawing 0.23 amps. (the defunct dehumidifier drew 7.5 amps.) As you can see in the drawings, the fan is mounted on a 1⁄2-in.-thick plywood tray with a circular cutout that corresponds with the diameter of the duct mounted below it. The tray slides into a 10-in.-sq. plywood box. The inlet and outlet ducts are 6-in.-dia. galvanized, smooth-wall sheet metal. The installation shown here exhausts through a plastic pane in a window. The exit pipe is screened at the end to keep out bugs when the fan is off, and the inlet is about 4 in. above the basement floor.

This thing definitely works & is the seventh one I have installed. For one house with a major moisture problem, I installed a 10-in.-dia. axial fan. The moisture problem was under control in the house within two weeks."