jacking a sloped floor

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jacking a sloped floor

Postby Tameca on Wed May 30, 2001 11:00 pm

I have an older home and one of the upstairs floors has a very bad slope to it, does anyone know how expensive it would be to have the floor jacked or has anyone ever had to do this before?


Re: jacking a sloped floor

Postby Kevin on Thu May 31, 2001 8:16 am

It all depends on what is causing the sloping. It could range from replacing joists to more serious structural problems that go to the foundation. Is it just one room, or the whole upstairs? It's gonna be big money no matter what, can you live with the tilt? My house is from 1835 and is sound, but the center of the house is about 2" lower than the outside walls. I kinda like it.


Re: jacking a sloped floor

Postby Doug E on Thu May 31, 2001 8:29 am

Get the car jack out of the trunk and jack away!


I'll start out with one of Newton's laws. For each reaction there is an equal and opposite reaction. Meaning in relevance to this topic. If you jack the ceiling to raise the floor above it, that force is also pushing down on the floor the jack sits on and the rest of the floors underneath the jack. To counter this, you need to support the jack on all floor levels as close to where the jack is located, so the jacking force is concentrated up where you intend it to be.

You can use a bottle jack (which you can find at tool rental stores)and 4X4 lumber, you can nail two 2X4's together, but I don't think they are as strong. I'm assuming you have the floor joists exposed, because I am sure this will crack any plaster/drywall on the ceiling.

It's good to know why the floor is sloped. How did it get this way? Did the joist crack from dry rot or water damage. What condition are they in? If you jack a floor with bad lumber, you may inflict more damage than good. Houses do settle, but if the slope is felt by walking, then something failed over the coarse of the years and you should determine what that was and repair it.(I.E sister or replace the joists)

The jacking part is fun, but realistically you should jack 1/2" or less every few days to allow the house to settle to it's new position. If you jack to your desired height -say 1.25" all at once you will crack walls, perhaps break window panes because the house/floor is moving at a rate it cannot settle fast enough.

You should also find out how the house was framed to get an idea of what potentially else will move when you jack the floor. It's easier to do in a gutted house, but doable in one where the ceilings and walls are still intact.Expect plaster fallout.

Sorry for the windy post. This is just a gist of what you may be getting yourself into.It's important to support the jack on all floors if you want results.

Good luck.

Doug E

Doug E

Re: jacking a sloped floor

Postby Rick B on Thu May 31, 2001 8:55 am

Even if its something they can live with I think they should still look into what is the cause of the problem. Ignoring problems only leads to bigger problems. As I'm finding in my own house the past owners "fixed" a lot of things but they only fixed them on a cosmetic level, never really addressing what the real problems where. Now as I get into redoing each room I'm uncovering problems that have grown in to much larger problems.

I'm not an expert by any means but I would take up part of the floor in the area where the slope is and inspect the joists underneath. I'm sure there are others on this board that can fill you in on what types of things you can look for. Our home inspector said to poke the beams with an awl or screwdriver to see if they've rotted or softened and to look for any signs of insects.

Rick B

Re: jacking a sloped floor

Postby richard on Thu May 31, 2001 9:43 am

It is possible a ground level sill is deteriorating (rotting) causing the structure to sag. Check to see if you have dirt contacting the wood or siding of your house foundation where the sag is. Could be a corner post has sunk a little due to the rot. A previous PO "fixed" water drainage this way on my house. But it created problems with the wood/soil contact. Good luck.

Re: jacking a sloped floor

Postby Don M on Thu May 31, 2001 10:52 am

Hi Tameca, All the suggestions above are good ones. You really need to determine why the floor is sagging before you can decide how to repair it. In addition to those above, which direction is the sag going? Poorly supported central stairwells and fireplaces that have floor joists tied into them can often also result in uneven settling and out of level floor joists. If you can provide more details about your specific problem perhaps we can provide you with other ideas. Don

Don M

Re: jacking a sloped floor

Postby Karen on Thu Jun 07, 2001 3:37 am

As houses settle, they might settle away from the chimney, which does not settle. i don't know if there's anything you can do about that. If it sloped toward one wall, find out what's holding up that wall. I saw one house where the wall had actually slipped off the foundation! In my house I have a dip at one end of the dining room china cabinet, caused by a weak joist in the floor. Fortunatly this is on the first floor, so I can go down in the basement, span several joists with a 4x4, and put in a post jack (Menards, Home Depot, etc). But I too was warned about jacking no more than half a turn every few days.


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