I know it's a how-long-is-a-piece-of-string question, but I'm just looking for a very rough idea of price. We're toying with the idea of extending our dining room out about 4 feet. The kitchen already goes that far. It's about 10 feet wide. There would be external plumbing issues as the pipes from the bathroom upstairs go down what's currently the corner between the kitchen and dining room and into a drain which we'd be looking to build over.