Ive used screw jacks and 1/4 inch plate steel , get the steel from a
scrap dealer. A problem could be the footing for the jack as a floor
will lilely crack if you just add another one beside it. Do you have a
screw jack or solid post. Best might be removing the post and insert a
screw jack support in its place. While suppporting it on either side
tempoarily so it doesnt fall.