We bought a 20 yr. old rancher and everthing is still original and shows a lot of wear. I want to start updating/remodeling one room at a time. I would like to lay ceramic tile in the entryway and in the bathrooms. My question is this. My wife has severe arthritis and doesn't get around very well at age 51, so I want to do everything with the thought that she may some day be in a wheel chair. She is pretty heavy and since the combined weight of her and the chair would be concentrated on a very small area (sq. inches) compared to someone walking upright, would I be likely to get cracked tiles or grout cracks after an extended period of time? Let's assume that the joists and subfloor are sufficient for normal installation/usage.