I have the same problem in my upstairs bedroom. The floor boards are gapped. The floor in that room sags to one side.we believe it was caused by a waterbed placed on the second floor.My bathroom flooded it was next to that bedroom,and now the drywall in my livingroom,directly under the bedroom is is bowing and the plaster in my dining room is beginning to bow. I am an amature also but i would appreciate any advice any of you can give. I feel like my house will crumble any day now!