Lifting a house to replace your foundation is a slow and challenging proposition. But if your foundation can no longer support the house safely, you must raise the house up so you can remove the old foundation and build a new one. House lifting requires multiple people and attention to detail for a safe project.
Things You'll Need
- 30-ton hydraulic house jacks
- Steel I beams
- 4-foot oak 4-by-4 inch beams
- Bags of ready-mix concrete
- 2-by-4-inch lumber
- Reciprocating saw
Obtain appropriate permits from local building authorities. Call your utility companies to disconnect gas, electric, water and phone lines at the point where they enter the house. Remove foundation hold-down nuts. Remove any other connections holding the house to the foundation.
Knock out holes in your foundation immediately below the sill plate. Make the holes large enough to pass the steel I beams that will support your house as it lifts. Position the holes at least 4 feet from the corners. You will need at least two steel lifting I beams, sized according to the weight and length of your house. Beams should be installed perpendicular to the direction of the floor joists. Extend the lifting beams at least 3 feet outside the house foundation.
Prepare a concrete base for each house jack. Dig a hole 2 feet in diameter and about a foot deep under each end of the lifting beams. Nail together a square form from two-by-four lumber with an interior measurement of 16 inches on a side. Place it on the bottom of the hole, level the form and fill it with concrete. Allow to cure for 48 hours.
Cut 4-by-4 oak beams into sections 16 inches long with the reciprocating saw. Lay four sections on the concrete parallel with the lifting beam. Stack four more sections at right angles to the first layer, if needed. Repeat in the other three holes. Top each stack with a building jack snugged up to the beam so it just starts bearing weight.
Build house support “cribs” out of the 4-by-4 beams. Site each crib inside the foundation, 3 feet in from the foundation wall. Lay two 4-by-4 beams parallel to the lifting I beam, 40 inches apart and directly under the steel beam. Lay two more beams perpendicular to the first. Lay two more beams perpendicular to the second. Continue laying up beams until the tower almost touches the steel lifting beam. Build three more house support cribs at the other ends of the lifting beams.
Put one person at each jack. On a signal, the four people should simultaneously pump one stroke of the jack handle. Pump the handle evenly through its stroke. Check that the jack supports and the house are stable. Pump another stroke. Check again for stability. Repeat until the jack has extended as far as it will go, typically 12 or 18 inches.
Stack more beams on the house support cribs as the house rises. Ease off on the jacks to set the house down on the support cribs. Retract the jacks, stack another layer or two onto each jack support, reset the jacks and pump the jacks to lift the house again. When the house is high enough, let the house rest on the house support cribs inside the foundation. You now are ready to remove your old foundation and build the new one.
Tips & Warnings
- Do not attempt this project unless you have experience with heavy construction. Mistakes can ruin your house or cause injury or loss of life.
- Do not work alone. This job requires a team of workers.