I'm thinking about finishing my basement and among several design considerations I'm wondering about floor drains. I have 3 in my basement and I think one or more do not have traps. This is something I will have looked into (adding traps!), but I'd also like more information so I can make a good decision as to if I finish my basement, how to deal with the drains. What is typically done? Can you finish over top? I imagine that you cant do that. Or do you cover over, but give access to it somehow? What about radon under the finish material that might come from the drain, or would the trap just stop that completely? Or is it necessary to have the drain fully visible? Not pretty! Finally what about flow back- I hear there is some device that acts to stop the sewer from backing up into the basement..
Just a thought about the drain without a trap.. It may be a LP drain.. If you have propane it's heavier than air so sometimes you might put in a drain to the outside but it's not a "Plumbing drain" as such.. no trap needed..