How can I level my basement floor, which has a 4-inch dip?

Question

I googled today on how to level a basement floor. Most people recommend using SLC (self leveling concrete)... I don't think I can just use that because of the pitch of my floor (and from what I hear, the price of SLC). The house was built in the 1930's and has settled since then. Its higher in the middle. About 3-4 feet away from one of the walls it start to dip and at its lowest its about 4 inches down.

So what I imagine I can do is this:

1. Clean the floor
2. Use some sort of primer so that the concrete sticks together
3. Pour regular concrete, so that it comes close to level
4. Once that drys use the primer on top of that
5. Pour SLC

Will the SLC be strong enough to support wooden beams for the walls - that will be butt up against the joists near the wall?

What would your recommendations be? Please note that I plan on finishing the basement so I will be putting horizontal wooden beams around the room with drywall in front.

As a bonus question. There are two wooden joists in the ceiling in my basement that are holding up my fridge in my kitchen (as well as a wall). They have warped (sagging) about 1/2 - 1 inch and I would like to put a supporting beam underneath it in the basement. What can I get to very gradually lift the beam back in place so that I can place the supporting beam underneath it?

Answer 1

I had something similar in my basement - a drain in the middle of the floor, and the floor around it sloped toward the drain.

We did pretty much what you described and it turned out really well

1. Clean the floor up nice.
2. Used a wire brush to roughen up the surface a bit so the new concrete will adhere well.
3. Poured in regular concrete to almost level it out.
4. Used thin-set mortar to finish it off (the same mortar you would use for setting tiles)

As for your sagging beam - they make special house jacks for that kind of stuff, but a hydraulic car jack with a 4x4 would probably do the trick as well (for your situation anyways).

Answer 2

You may want to google "concrete leveling" in your area. There are companies that will come out and pump concrete under the floor to raise the level back to where it was. This will likely be a better solution, and may prevent further settling in the future.

For your "bonus" question: A cheap bottle jack with a 4x4 should be sufficient to lift the studs back into place.

A side note:
You may want to think about getting a structural engineer out to your place before you attempt to fix either of these problems. The large amount of settling may be pointing towards a larger problem that you would be masking by just leveling it off. The beam sagging is also alarming. If there is too much load placed on that section of the floor, you may have other (and perhaps larger) structural issues that may or may not be readily apparent to you. Also, the floor which will support the new beam may not be sufficient to handle the extra load from above.

It is likely worth the couple of hundred dollars to make sure your repairs will, in fact, fix the problem instead of just masking it or creating larger problems.