How To Jack Up A Sagging Floor

Foundation repairs are the most expensive reason for sagging floors in old houses.

How to jack up a sagging floor. A common scenario is to install temporary jack posts and support beams then permanent posts and beams over new footings. A taut string stretched across the floor will show the amount of deflection and improvement. Compound can correct sags and dips as deep as 1 1 2 inches. 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.

You ll need to hire a structural engineer or foundation specialist to jack up and level the house and then shore up your home with pilings beams or even put new footers on the foundation. The solution to sagging floors or the damaged sills and joist ends that contribute to them often involves jacking. Continue to raise the jack until you feel some resistance. In this style framing the entire structure will sag in that area usually causing cracks in walls ceilings or doors rubbing their frame you will need a proper footing under the post jack because your lifting much more weight if your correcting a sagging interior floor in ether style framing locate the main support beam in that area the large beam that the floor joist are sitting on raise that area keep in mind if its drastic have the foundation evaluated.

If you have access to the basement or crawlspace it is possible to jack up saggy joists until they are level and then sister them so that they remain straight after the jacks are removed. The jack should be placed directly beneath the center joist. Make sure that the lumber or lally posts are perpendicular when jacking or they may slip out of position. When this happens stop hoisting the jack and lock it in place.

Carefully hoist the jack until the beam reaches the floor underneath. Stand your floor jack between the two beams on top of the one that s on the floor and turn the thread on the jack until it wedges under the top beam. Underneath the floor in a crawl space or basement position the floor jack or jacks and place the beam in position.