Paul in MN
Well-known Member
I should have added this to the earlier discussion, but as it has rolled back, I'm going to do this as a new thread.
A couple of thoughts about successful and safe lifting.
1) Make sure your jacks and their supports are in good level. When jacking up houses for moving, we even use a level on the ground pads to be sure they are level. Make sure your blocking above the jack is cut square if you are using it vertically. Keep the vertical extensions of the jack relatively short.
2) Wood members used as pads are likely to crush if used horizontally. Sometimes as they crush, they split and throw the jack sideways. Look at the grain of the wood and pick pieces that have tight grain. Wide grain is poor, weak and likely to split. Wood pads made from a decent 3/4" plywood are much less likely to split and crush. Good pieces of Oak work well.
3) Do not jack against the wood pads or house beams. The head of the jack will compress the wood or beam and begin failure. Use a 3/8" thick steel pad against the wood member to keep the wood from crushing. Spread out the forces.
4) Make a big pad on the ground to jack from. I'd guess from what you have described, that 2 ft by 2 ft would be good. The soil is unpredictable as to what it will support, so spread out the load.
5) If any of your supports begins to bend or twist, set up a jack and support system to both sides of the failing member. Do not suddenly release the lift pressure from a beam by taking out the failing jack, the beam may crack.
6) Do not trust hydraulic jacks to hold a steady load. They are notorious for leaking down in less than a day. So use them to lift and then provide support blocking with shims to tighten up the load against your blocking. Support blocking must not be left loose, but needs to be preloaded so it stays in place if failure begins.
7) Think "forces" and their directions. Extra blocking is much better than too little. Screw jacks hold, hydraulic jacks just lift but can not be trusted to hold.
Good luck!!
Paul in MN
A couple of thoughts about successful and safe lifting.
1) Make sure your jacks and their supports are in good level. When jacking up houses for moving, we even use a level on the ground pads to be sure they are level. Make sure your blocking above the jack is cut square if you are using it vertically. Keep the vertical extensions of the jack relatively short.
2) Wood members used as pads are likely to crush if used horizontally. Sometimes as they crush, they split and throw the jack sideways. Look at the grain of the wood and pick pieces that have tight grain. Wide grain is poor, weak and likely to split. Wood pads made from a decent 3/4" plywood are much less likely to split and crush. Good pieces of Oak work well.
3) Do not jack against the wood pads or house beams. The head of the jack will compress the wood or beam and begin failure. Use a 3/8" thick steel pad against the wood member to keep the wood from crushing. Spread out the forces.
4) Make a big pad on the ground to jack from. I'd guess from what you have described, that 2 ft by 2 ft would be good. The soil is unpredictable as to what it will support, so spread out the load.
5) If any of your supports begins to bend or twist, set up a jack and support system to both sides of the failing member. Do not suddenly release the lift pressure from a beam by taking out the failing jack, the beam may crack.
6) Do not trust hydraulic jacks to hold a steady load. They are notorious for leaking down in less than a day. So use them to lift and then provide support blocking with shims to tighten up the load against your blocking. Support blocking must not be left loose, but needs to be preloaded so it stays in place if failure begins.
7) Think "forces" and their directions. Extra blocking is much better than too little. Screw jacks hold, hydraulic jacks just lift but can not be trusted to hold.
Good luck!!
Paul in MN