Jacking up a floor and leveling it is easy with these simple instructions. Make repairs to settling piers and weak joists to fix swagging floors and roof lines. The only tools required is a bottle jack, string, straight claw hammer, circular saw, and a light source. You will need some bagged concrete, concrete blocks, lumber, and several sixteen inch boards for supplies. The crawl space under a house can be a hazardous environment. Make sure you have a quality light source that is not going to burn down the house.There may be plumbing, electrical, or HVAC services to contend with. Stay away from them as much as possible. If there is a moisture control problem then it should be addressed first.
Jacking up a Floor and Leveling it
Identify the problem as load bearing or non-load bearing. If there is wall on top of the swagging area, then it is a load bearing problem. This means the beam beneath the wall is not of sufficient size to carry the load. If this is the case, then you may want to enlist the help of professionals. For the purpose of this page, the focus will remain on non-load bearing repairs.
The problem area will involve a set of floor joists that area spanned too far. The idea behind this procedure is simple; place a girder on top of piers below and perpendicular to the joists to hold them at a level position.
The girders can be no more than 12′ long each. If the room is wider, then use multiple girders. Establish a center and dig footings with a straight claw hammer 24″ x 24″ by 12″ deep. These footings should be no more than 7′ apart. Premix some bagged concrete and pour the footings full. Level the tops and allow the mix to set for at least two days. Build a girder from the outside footing to the outside footing. Place a jack on the inside edge of each outside footing. Block under each one until there is just enough room to fit the girder between the jacks and the joists. Slowly jack up the floor. Use a string to watch the floor come up. Keep an eye on the girder so that it does not get out of position and try to roll. Once the floor is at the right level, jack it up just a little bit higher. Stack 8 x 12 blocks two wide in a criss-cross pattern until they as close to the bottom of the girders as possible. Use 1 1/2″ blocks to close the gap. Finish off the piers by ripping shims to make the fit against the girders as tight as possible. Release the jacks. Move the jacks to any inside footings and repeat the procedure.