What kind of bugs and how high is the deck from the ground.
How to keep bugs from coming up through deck floor.
My first thought was to lay marine grade plywood over the decking but given the potential for water to enter through the screen and lay on the floor i m a bit leery.
It seems screening the underside of the joists has the potential to trap debris that falls through the cracks.
The underside of a deck can provide a nice shady area for a variety of crawling creatures to make their home.
So it has the basic kind of 2 4 style decking on the floor.
This stops bugs from coming up through the floorboards of the deck.
Traditional decking has a 1 8 or 1 4 gap between boards which is more than enough room for mosquitoes or other bugs to crawl through.
If you re concerned about bugs coming up from the gaps between floorboards you may want to place a screen under the deck floor.
Cover the gap between the deck and the ground with a skirt made of pressure treated or composite plywood.
The crawlspace beneath is open as it is a post on pad foundation.
In order to effectively protect against bugs a screen porch must be completely enclosed but if your porch wasn t well built from the start it is often the deck floorboards that were overlooked.