I wrote earlier I can feel the cat walk across the floor-- while sitting in the sofa chair this has increased over the a short period of time. The cat weighs 7 lbs. This is the only house I have ever lived in that I have had this problem. What is wrong with this house??
A couple of things--
If you have a floating floor, in other words a laminate floor which is made of very thin lightweight planks and someone didn't insulate or put some form of lightweight insulation underneath this type flooring, it could very well transmit that type of 'feeling' across a region of the floor and allow to you sense your cat walking.
It could be, the joists underneath the house are sagging and there is some foundational issues associated with settling, or partial joist rot which would allow the floor to move under foot fractions of an inch or so. Thereby, either scenario would allow to feel someone or your cat walking like that.