Q: I’m building a work-shed supported by concrete blocks, but I live in a cold climate so I’d like to enclose the space beneath the floor to keep out drafts (and critters). What do you recommend I use that would be both economical and durable?
A: You might try using some 1/2-in. thick cement boards attached to the sill beams. Bury the bottoms of the cement board panels at least 6 inches underground, which may require cutting the panels and/or digging a trench. Your lumberyard will sell special screws for attaching the cement board to the frame. Cover the joints between panels with fiberglass tape, and mortar cement to cover the tape and corners.
