It takes lots of jacks to raise a house (5ton Minimum). Set a row of jacks under a beam and raise it about 1" and block it, move to another beam and repeat, continue until the beams are all raised and start over again. It is a good idea to check the floors occasionally to make sure they are staying level. Some small adjustments here and there may be necessary to keep it all level. This is best not done in high winds or rainy weather because the house will be very unstable.