How To Jack Up Floor Joists

Adjust the screw jack up or down to achieve a level surface.

How to jack up floor joists.

If a crack or sag is isolated to one area the sister joist should extend at least 3 ft. The steel plates should be a minimum of 25 inch 0 6 cm thickness and large enough to distribute the full load of that jack across the beam. 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.

Stretch a string across the floor to evaluate the amount of deflection then use it as a benchmark for improvement when jacking. It is critical to use heavy steel plates between the jack and the beams to avoid crushing wood fibers in the beams destroying their integrity or worse yet punching a hole through the floor. Lower the hydraulic jack to transfer the floor load to the new screw jack. Where these repairs are not sufficient also consider shoring up joists or beams that were cut drilled or notched for pipes wires or ducts.

Drive 16 penny nails through the holes in the plates and into the wood framing. On both sides of the problem area. Set a hydraulic jack and post under the beam and jack up the joists about 1 8 in. Tiger brand adjustable floor jack model js 15 15 gauge floor jacks telescoping jack for temporary support size range 1 1 3 4 4 out of 5 stars 368 19 67 19.

Adjust the screw jack so that the top and bottom plates are flush to the wood surfaces above and below. Well after doing the navy seal crawl up under the house we found that the joists that were supporting that floor were not actually attached to the sill plate any longer as seen in the photograph below. A day until they re level. Wooden shims are often used to work out squeaks and stabilize spongy areas but they can also be used for slight adjustments to specific places.

Jacking up a floor and leveling it is easy with these simple instructions.