How To Jack Up A Floor
Shows raisinge a sagging floor gradually with bottle jacks.
How to jack up a floor. After they were in place we hoisted up the 4 x6 x8 beam so that it crossed all four of the new joists sliding the screw jacks underneath. The 4 inch lally posts can be replaced by 6 x 6 inch lumber. The solution to sagging floors or the damaged sills and joist ends that contribute to them often involves jacking. Make sure that the lumber or lally posts are perpendicular when jacking or they may slip out of position.
You will have to make sure your joists can handle the addition of considerably more weight from the plywood subfloor and any floor coverings. Continue to raise the jack until you feel some resistance. A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too. A taut string stretched across the floor will show the amount of deflection and improvement.
Underneath the floor in a crawl space or basement position the floor jack or jacks and place the beam in position. By jacking up the ceiling of the basement you. Use a hammer a nail puller and a sledgehammer to remove the existing underpinning wood post and nails. Slowly jack up the floor.
Once the new joists were up we found locations where the concrete blocks could sit flat on the ground so the pressure wouldn t cause them to crack. Raise each jack by 1 8 inch at a time this will help to reduce any damage to window frames and plaster or drywall walls above the floor. Use a string to watch the floor come up. When this happens stop hoisting the jack and lock it in place.
On the top side of the floor another fix it idea to lay down new hardwood over the existing floor. Carefully hoist the jack until the beam reaches the floor underneath. Center the screw jack below the girder and on top of the wood block on the concrete pier. Use a hydraulic jack and a short post to shore up the floor during this process.
Block under each one until there is just enough room to fit the girder between the jacks and the joists.