How To Jack Up A Sagging Floor

A dip in the floor anywhere in the house is the beginning of a long queue of problems. You may even notice that the door near the sag might not even close properly. Before you start panicking, let me stop you right there. As haunting as this problem seems, there is a way to fix it.

No doubt, a sagging floor is quite a major problem, but you do not need to be a handyman to be able to fix it. With the proper tools and the right guidelines, any person can jack up and fix the sagging floor of their house.

Take it from me, all I needed were a couple of videos, but lucky for you, those won’t be needed. Every single thing that I learned from hours of research and from my own experience has been shared in the article below. So, give it a read and fix your sagging floor without spending any extra time on research.

How To Jack Up A Sagging Floor

By following the below-stated steps, you will be able to jack up the sagging floor of your house very easily.

Items Required

In order to be able to fix the sag in the flooring of your house, you first need to collect a couple of tools. Having the right tools is a critical step, as it will help in solving this issue without any inconvenience. First, you need your bottle jacks, a measuring tape, a couple of nails, a thread, a hammer, a wrench, and a few tall pieces of lumber. The length of the lumber depends upon the height of your flooring.

First Step

Now that you have compiled all of your required tools, it is time to get down to business. First, we need to measure the floor to find out how much it has sagged. For this part, we need the thread and nails. Take the nails and hammer them into both of the walls of your basement that are facing each other. Now take the thread and tie it to the nail on one wall and then take it all the way to the nail on the other wall and tie it. Make sure that you tie the thread at least 2 inches below the top of the floor joist, which is basically supporting the weight of the house.

Second Step

Now take your measuring tape, and measure from both ends. Hold it to the ceiling, and bring it all the way down to the thread. Once you have taken the measurements from the sides, move to the area of the sagging, which should be in the centre. Now take measurements from that area. You will notice that due to the sagging, the final measurement is lower as compared to the side ones. The difference between the side measurements and the one from the sagging area is how much the floor has sagged. That is precisely how much we need to jack it up.


Third Step

Now take your hydraulic jack and place it right under the sagging area. Take the lumber block and put it right on top of the jack. A critical step here is that we are going to be using lumber pieces in both vertical and horizontal positions. Place one block under the floor joists horizontally. So when you place the lumber block vertically on the hydraulic jack, it should come in contact with the horizontal one. Make sure to use your hammer to push the vertical one in its place. You can also use nails to screw the lumber to ensure it does not move.

Fourth Step

Once all your tools are in their place, it is time to start jacking. Take your wrench and start jacking the hydraulic jack. Make sure not to twist it all the way in a single go. The key here is to give it small twists so that the floor joist gets raised without cracking due to sudden pressure. After a couple of twists, take your measuring tape and measure the sagging area again. There will be a decrease in the sagging. Keep repeating the process till the measurement from the sagging area is the same as the ones from the sides.

Fifth Step

To be on the safe side, take two jacks, place them on both sides of the first jack and repeat this step twice on both of them. It will help in distributing the weight evenly throughout the floor joist. However, make sure that you do not place the jacks too close to each other. There should be a minimum distance of 5 feet.


Having even half an inch of sag in the flooring of the house can lead to big problems. Therefore, before things get too dangerous, you need to take care of the sagging floor. The article above will help you every step of the way with clear and precise instructions.


Janathan Greez
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