Floor joist rose off of support stringers

[cthekaiser]

120 year old house. I just finished laundry in my basement and leaned back against a 8x8 support beam and it moved. Confused I turnt around and pushed it again and it moved again.

Standing back I notice the floor joist is about 1/8 an inch above the stringer. All floor joist are still resting on the foundation walls. The brick walls of the house don't seem to have and fault lines or cracks.

The house use to be 2 stories years ago until a fire, and it was rehabbed into just a single story, that's why the huge support beams. Also I'm in St. Louis and we're having some freeze and thaw cycles.

Any ideas?

 

[Snoonyb]

Welcome.

If the floors bounce, jack the beam up and replace the post, or, just drive some shims between the post and beam.

 

[Steve123]

The house has lasted 120 years on those joists. I would just leave it.

 

[cthekaiser]

Welcome.

If the floors bounce, jack the beam up and replace the post, or, just drive some shims between the post and beam.

I replaced the beams about 8 months ago.

No bounce that's noticable yet. This had to have happened within the last week or so but...

The part of the house with these floors, is being re-rehabbed. I knocked all the plaster off the walls and ceilings. The weight taken off could have caused the joist to rise free maybe?

 

[cthekaiser]

The house has lasted 120 years on those joists. I would just leave it.

Joist seem fine, I'm concerned as to why the joist have separated from the support stringer's.

Any ideas?

 

[cthekaiser]

I replaced 4 of 5 support beams about 8 months ago. The one that has the separated floor joist I notice almost everytime I go into the basement as I haven't trimmed the 2x4 with a sawzall yet.I know this has happened within the last week but I'd like to say last few days honestly.

House is still structurally sound right?
Any ideas are appreciated.

 

[Bob Reynolds]

What's the footing look like where the support posts meet the floor?

 

[cthekaiser]

What's the footing look like where the support posts meet the floor?

It is concrete, but not very much. 2 1/2 maybe 3 inches. This particular 8x8 was sitting on broken concrete. I removed the broken concrete and replace with the same.

Post script: about a week after replacing the beams, I had a pipe break. The valves in the house were frozen and the valve at the curb was too. All lead. My basement flooded completely for about 5 days(that's why the water stains on 8x8) then the water started sleeping through cracks in the floor for another month..... Until I could get a plumber to run a completely new water line. I was worried about the dirt under my house moving with how much water went under the concrete floors.

Thank you everyone for replying.

 

[Bob Reynolds]

Well, it looks like what was left of your footing has sunk. That post needs to be supported so that it will not sink.

I'm not sure where you are, but in my part of the country (North Carolina), we have 12-14 inches of concrete on stable soil for a footing. IF the soil is not stable, I have had to pour footings over 20 feet deep and fill them with concrete.

Your foundation is the most important part of the house. It holds everything up.

 

[cthekaiser]

Well, it looks like what was left of your footing has sunk. That post needs to be supported so that it will not sink.

I'm not sure where you are, but in my part of the country (North Carolina), we have 12-14 inches of concrete on stable soil for a footing. IF the soil is not stable, I have had to pour footings over 20 feet deep and fill them with concrete.

Your foundation is the most important part of the house. It holds everything up.

I'm going to jack hammer it all up and put a much thinker slab

 

[Bob Reynolds]

Keep in mind that the concrete that is UNDER the post must be much thicker than the floor. The floor may be 4 inches thick but the other part is much thicker. The part under the posts might need to be up to 30 inches thick. The depth will depend on where you are and what the local code requires.

Here is a picture that I found of an existing floor being demolished and footings being constructed under the new posts. The area under the posts has been dug down to an unknown depth and filled with concrete. It also has to be spread out to carry the load. In this photo, it looks like they dug a 20-24 inch wide hole and filled it with concrete under the posts. While this is going on, the support beam above is being temporarily supported with wooden 4X4's.