The floor being described is in the kitchen. It's possible that the rich red tile has been replaced with the cheaper, and more easily cleanable, speckled linoleum, which was popular at one time. There may have been a dot pattern, as well. But in any case, it is as dojibear describes:
The short story is on the Ellery Queen Mystery Magazine (PDF). I read that section and the only new information I got was for the kitchen.