Checking For Level Floor Framing
It's not uncommon to have a floor out of level.
Especially if the home is old and suffering from wood damage. Simply
place a level on the floor to see if it's good or not.
In the picture above, the level is placed over the floor joist, to give the Carpenter a general idea about the condition of the floor.
Home Repair Tip : Longer levels can be used as straight edges to check for irregularities in the floor framing. The 6 foot to 8 foot long levels work ideally to check the floor joist for highs and lows.
To Check the Floor: Set the 8 foot level perpendicular on top of the floor joist. Start from one edge of the room and work your way towards the other, placing the level on different areas of the floor framing. If the level teeter totters on a floor joist, it can be planed down using an electric planer, until it's level with the other floor joist and isn't teeter tottering anymore.
If the floor joist is low, you can add cardboard strips or additional wood furring, to bring it up to the correct height.