Anybody with a screened porch in a buggy part of the country knows that bugs will get in anywhere they see opportunity — even through the floors. Jerry Germer pointed that out in his article A Screened-porch Addition. But he also noted that his method of stapling screen to the top of the joists made it tough to keep the spaces between the boards free of debris. The drawing shows the system I use to make removable screens that are affixed to the undersides of the joists.
Each 4-ft. by 8-ft. screen has a 2×2 frame with a spreader in the middle. The 4-ft. dimension is convenient because most decks are framed with joists on either 16-in. or 24-in. centers. The screens are held in place by cleats on one end and on the other by wood blocks that pivot on screws. I try to cover as much of the underside of the deck as possible with this module, but usually there are projections for bracing and other obstructions that require permanent screening around them. That’s okay as long as you can reach in from the side to clean the screens.
This isn’t an easy or inexpensive way to de-bug a deck floor. But in 10 years of deck building, it’s the best solution I’ve come up with.
Al Fink, Lynchburg, VA