[jaketrades]

I've got a staircase in my remodel project that is sagging to one side pretty badly.

The floor joists run perpendicular to the stairwell and the stairwell is right next to the boundry wall. It's an attached home in Brooklyn, NY. 100 years old.

From what I've seen in an abandoned dumb waiter (shaftway) in the center of the building, the carpenters notched the joists and the blocking to connect the floor joists across the span of the building. They cut a "nipple" on one side of the floor joist right before the dumb waiter which inserts into a notched hole on the blocking. What is that type of framing called?

I'm assuming this is what was done with the stairwell. Back then they didn't have joist hangers to more solidly connect the joists.

When viewing the staircase from underneath the left side is sagging 1 1/2" lower than the right.

Can I attach a Jack post and slowly lift the sagging portion? Say 1/8" per week? And when I got it close to level sister with 2x10's? And attach the old joists with joist hangers.

From what I've read online I need to slowly lift the beam so it doesn't crack. Stress the beam out 1/8" and let it find some comfort at that raised point in a week. Then raise it another 1/8".

I realize this will cause cracking of drywall & plaster, etc. But I'm ok with that. It's all getting replaced.

 

[Nealtw]

The joist for the floor are likely over spanned and today the last one would be double and the one above the stairs would be double. back then they had a different idea. Instead of 2 and 2 they went with half and half.




If you are going to loose the plaster, do that first, if the walls on both sides are bearing you might cut all the joist and put a beam in or support it right from the basement with posts at the corners.

 

[jaketrades]

Forgot to add: The floor joists span close to 20'. They are rough sawn. Most are 3"x8". And some are 4x8".

 

[Nealtw]

Forgot to add: The floor joists span close to 20'. They are rough sawn. Most are 3"x8". And some are 4x8".

And with old growth it likely stood up for years but that one will be a bear to straighten.
Are both walls brick, I don't know how you would get bearing off that today but i am sure there is a way.

 

[jaketrades]

And with old growth it likely stood up for years but that one will be a bear to straighten.
Are both walls brick, I don't know how you would get bearing off that today but i am sure there is a way.

The boundary walls of the building are brick noggin. But the support structure is wood framed.

 

[Nealtw]

The boundary walls of the building are brick noggin. But the support structure is wood framed.

So with noggin the beam will take the load and you can use a hanger.
That should work, at least until you see what you have. :biggrin2:

 

[Mystriss]

It looks to me like someone cut out a column...

 

[jaketrades]

It looks to me like someone cut out a column...

Interesting point. I don't see a spot where the support post would have been given that the low point is in a hallway.

All the houses here were built around the same time. I don't recall seeing a post in any of the other houses I've been in.

 

[jaketrades]

Finally got around to cutting open the ceiling underneath the sagging staircase. I found a the sagging joist underneath the staircase. It's attached to a a joist running parallel to the stairwell opening. Can I jack up the sagging joist with a jackpost and some 4x lumber to get the staircase closer to level?

Here are some pics:

 

[Nealtw]

Finally got around to cutting open the ceiling underneath the sagging staircase. I found a the sagging joist underneath the staircase. It's attached to a a joist running parallel to the stairwell opening. Can I jack up the sagging joist with a jackpost and some 4x lumber to get the staircase closer to level?

Here are some pics:

Careful how much weight you put on the floor below.
What is the plan when you get it jacked up?

 

[3onthetree]

Isn't the joist you are pointing to as sagging a full width joist across the entire townhome (joist in red, blue circle the part you are pointing at, yellow other joists)?

 

[kwikfishron]

As Neil mentioned be real careful about jacking off the floor.

I've dealt with a couple of these almost exactly to what yours looks like in 100 year old homes.

Each time once I got my jack point figured out I went to the basement and added a temporary post to create a direct load path down to the basement slab.

It was easy to do because there was a double joist running parallel to the stair that the stair was actually sitting on.

Doing that should guarantee that what you're jacking is going up instead of pushing the floor down.

 

[jaketrades]

Isn't the joist you are pointing to as sagging a full width joist across the entire townhome (joist in red, blue circle the part you are pointing at, yellow other joists)?

It's not a full width joist. It spans from one side of the townhouse to the opening for the stairwell. On one side the sagging joist is resting on the shared rim joist (??) of the attached houses. On the opposite side it is nailed into the joist running parallel to the stair opening. This parallel joist runs perpendicular to the house joists.

I'm wondering if the parallel joist is sagging as well. It might be cracked. I need to take a closer look.

 

[jaketrades]

Careful how much weight you put on the floor below.
What is the plan when you get it jacked up?

I used a plumb laser to find the jack post location on the ground. Looks like I have to be on the first stair tread to get under that joist. I'm not sure if that's a good idea.

 

[jaketrades]

As Neil mentioned be real careful about jacking off the floor.

I've dealt with a couple of these almost exactly to what yours looks like in 100 year old homes.

Each time once I got my jack point figured out I went to the basement and added a temporary post to create a direct load path down to the basement slab.

It was easy to do because there was a double joist running parallel to the stair that the stair was actually sitting on.

Doing that should guarantee that what you're jacking is going up instead of pushing the floor down.

Yeah that's a good point. Looks like I need to cut my basement ceiling open as well.

 

[kwikfishron]

I'm wondering if the parallel joist is sagging as well. It might be cracked. I need to take a closer look.

I also want to stress on another point that was made earlier.

Before you go any further you need to open the area up, meaning that any drywall, plaster and lath that you know is going to be replaced in that zone needs to go first.

That needs to happen before you even touch a jack.

 

[kwikfishron]

Looks like I need to cut my basement ceiling open as well.

Not necessarily, you should be able to determine from above if you have an adequate framing member under the jack point. If you do then there should be no reason tear up anything down there.

To protect the ceiling you would need like a hunk of 2x12 or something against the finished ceiling and then your temp post would attach to that.