How To Lift Or Jack Up Sunken Floor Joists

Jacking up the deck and shimming the post can resolve deck sag problems.

How to lift or jack up sunken floor joists.

It has to be jacked up slowly over days or even weeks to avoid cracking drywall plaster windows and even structural elements. Identify the area of the deck that is sagging and locate the support post that needs to be shimmed. Anything involving 20 ton house jacks will take time. Raise the jack so it contacts the wooden floor joist supporting the decking.

Once the new joists were up we found locations where the concrete blocks could sit flat on the ground so the pressure wouldn t cause them to crack. After they were in place we hoisted up the 4 x6 x8 beam so that it crossed all four of the new joists sliding the screw jacks underneath. Jack up that portion of the house and place new footers. Generally there are posts and beams under the floor joists.

Get the jacks under the floor. If a pier that the post is standing on has sunk into the ground you will need to lift the beam off the post and replace the post with a taller one.