[slowjo]

Hey guys, the backside of the house has sank becasue the sill plate completely rotted out (more about it on this thread). So we have been raising it. Its an 1882 colonial. It has ~25' 2x8 joists that span ~12' sections. So they sit in the middle of the span on a center beam.

The house dropped 4 inches at least in the back. We raised it about 2.5 inches so far. For some reason I thought the joists were 12 footers that were notched onto the center beam. I noticed they were not when one of the middle columns was bearing no weight at all. In fact the center column was not bearing any weight either. Today the house settled back on the center column, but not the other one. Here is a picture of the basic layout of the basement and the jacks.

The center column is not supporting much, and the column to the right is free.

The plan is to raise the house another 2 inches so we can put in a sill plate. Cut the rott from the joist ends and use joist hangers. Masons are replacing all the brick on that back wall with block as well. It was badly damaged. I am worried about the joists supporting all the weight of the house. They are 2x7 3/4 old lumber.

I guess my questions are what to do. Should I be worried about the joists stressing too much, or the foundation on the far side carrying more weight?

Should I shim the center middle support columns until they become weight bearing? (They are 10x10 timbers, middle column may be 12x12).

Should I take this opportunity to replace the center supports with something different? The wood seems in good shape.

Thank you,
Josh

 

[Ron6519]

It sounds as though, when the sill failed over time it put an arch into the joists as they were bent over the middle support columns. When you raised the damaged sill section, the arch remained and the joists lifted free of the supports. If the middle section has begun to lower, the other sections may follow.
If you want to minimize the pressure on the other side of the foundation, you might want to temporarily install another series of jacks in the middle to carry the center weight. Over time you can lower the middle section so it rests on the support beam. If it doesn't relax back, you can always install permanent shims so the weight is evenly distributed.
Who knows how long, if ever, it will assume it's original position.
Ron

 

[Just Bill]

It took 127 yrs for things to get where they are/were. Don't expect it all to fall exactly into place instantly. Wood just does not act that way. I have to wonder what kind of support is under the posts, they may have also settled over time. Getting back 4" on part of the house has to stress things quickly and much of the structure will not be happy. Doors and windows will jam, plaster will crack, etc.

 

[Scuba_Dave]

I would definitely put temp support in the middle

You are risking having the joists snap

 

[slowjo]

I'm planning on getting some support jacks under the carrier beam today before we go up any further. All plaster has been removed in the house except for 2 rooms, 1 of which has cracked. Its been expected. Nothing seems to be messed up structurally as far as I can tell. Just a lot of popped tiles, and crooked doors/windows.

thanks guys!

 

[Shamus]

I'm planning on getting some support jacks under the carrier beam today before we go up any further. All plaster has been removed in the house except for 2 rooms, 1 of which has cracked. Its been expected. Nothing seems to be messed up structurally as far as I can tell. Just a lot of popped tiles, and crooked doors/windows.

thanks guys!

WOW!
I've done a few of these over the years and you really need to get some weight transfered to that center beam and do it before you do anything else. Make sure you continue to keep weight on it as you go up.

Just an FYI. As mentioned above, it's taken years to get to the point where you began. It's a bad thing to try and get the entire building re-adjusted to it's original height quickly. When I raise a structure I always take months and bring everything up in 1/4" increments and let the building relax for a week or more before continuing. I'm refering to three story homes so a single story would be somewhat less of an issue. Even then it still can cause problems you didn't think about before-hand.


If you look at the studs on any exterior wall on that half of the house you will see where they are pulled away by the settling on both the top and the bottom. Your trying to get the entire support structure back to level, front to back and side to side. My 2¢ is go slow and keep the joists and beam supported at all times.

Be Safe!

 

[Ron6519]

I don't think the total joist deflection goes back 127 years. The issue started, when a previous homeowner installed a concrete slab next to the house, trapping water against the sill and rim joist. That's why I suggested an adjustable center support so it could be lowered over time. How long you keep it there is up to you. At some point you might want to put up some thing permanent. It might take 10 years to lower to the supports. As you put weight back in the house, gravity will help the process.
Ron

 

[Maintenance 6]

First, I would get a laser level, transit or even a simple water level, if you don't already have one, and figure out whether the beam is out of level with the sill plates. Second, since you have already gone 2-1/2 inches out of the 4 that you need, I would continue. I would, however, add a temporary beam with some adjustable teleposts next to the existing beam and sneak those up as you jack the rest of the house. After you have the sills repaired and transfer the load onto your new sills, I would lower the teleposts slowly, just keeping some weight on them. That will transfer the load back onto the existing beam as the structure starts to settle, as I beleive it will in time. If the existing beam is out of level with the sills, then you'll need to raise or lower the beam into place and shim accordingly. Since you have the plaster removed, it will be easy to have a look at the joints of the wall studs, top and bottom plates, etc. to see if anything is pulling apart where it shouldn't be.

 

[slowjo]

Thanks guys,
Today we put some post jacks under the main support beam next to the support columns. The house actually usses a chimney as support of the center beam as well. I will need to get a few more jacks to properly support the center beam. Im not sure how much weight I should put on the jacks. I went till the felt like they were getting hard to turn and I could see the center beam no longer lifting into the joist. It wasnt very far.

The doubled joist that runs down the center of the house is a 2x8 and a 2x6 together. My support bean for my jacks is cutting into the 2x8 about 3/8". So I put another jack and a long metal plate right on the joist between it and the center beam to help spread the weight. I cant pu it on the other side becuase the masons are workign there.


Today we cleaned up the lot, we had dug a french drain acroos the property and there wer still some ditches and a lot of dirt and rocks to get rid of. Took us all day, the tractor I have is kind of a POS though

-josh

 

[mdewii23]

First, I would get a laser level, transit or even a simple water level, if you don't already have one, and figure out whether the beam is out of level with the sill plates. Second, since you have already gone 2-1/2 inches out of the 4 that you need, I would continue. I would, however, add a temporary beam with some adjustable teleposts next to the existing beam and sneak those up as you jack the rest of the house. After you have the sills repaired and transfer the load onto your new sills, I would lower the teleposts slowly, just keeping some weight on them. That will transfer the load back onto the existing beam as the structure starts to settle, as I beleive it will in time. If the existing beam is out of level with the sills, then you'll need to raise or lower the beam into place and shim accordingly. Since you have the plaster removed, it will be easy to have a look at the joints of the wall studs, top and bottom plates, etc. to see if anything is pulling apart where it shouldn't be.

I think this is the best idea make sure your sills are level then adjust the center beam accordingly.