Dear James: I could use a long bench on my deck to use when entertaining. Are there low-cost, simple-to-build bench designs that I could make myself? —Mark B. Dear Mark: Building a deck bench is one of the most common do-it-yourself projects. It would be wise to make two benches while you are at it. The material costs, which are really high now, will double, but you can cut two of every part at the same time. It seems like you can never have too much seating with entertaining. Building a movable bench design offers more flexible usage. A movable bench uses slightly more material because it must be self-supporting and stronger as compared to one rigidly attached to the decking or railing. For the slight additional cost, a movable one certainly makes sense. You may also find other uses for it around your house. Even if you build movable …