Increase the damping of the floor by adding extra components to the room or rooms. Add drywall to the ceiling, erect a partition wall in the room or add extra furniture and fixtures on the floor to lessen the vibration.
Relocate the source of the vibration if possible. As an example, move your laundry room from upstairs to the basement or move a stereo system to another room. Move machinery or people closer to columns to lessen vibration in an office or commercial building.
Rearrange items in the room that vibrate to make the noise less noticeable. The floor vibration may still remain, but you won’t notice as much.
Obtain rubber vibration dampening pads to place under your washer or dryer, if they are the cause of the floor vibration.
Add rubber insulating sleeves or caulking to plumbing pipes so they don’t touch one another or any parts of the floor joists or frame.