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Jacking up 2 story house


tannerbanner's Avatar
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03-17-06, 06:12 PM   #1  
Jacking up 2 story house

Hi--We have an early 1900's house that is two-story and the supporting walls in the basement are approximately 4 feet away from the two main load bearing walls on the upper two floors. As you can imagine there is quite a problem with sagging joists. I'm not sure how this happened, whether they built it that way or I had one guy say he thought maybe the house had been moved onto the basement and they had mismeasured. Anyway, we are planning on running a laminated beam (doubled) under these two walls (they are perpendicular) and then jacking them up. One section on the basement has a cement floor--do I need to tear that out and place new footings or can I use steel plates to distribute the weight across a larger area? On the other side where there had been a wood floor, they put in 2x4's and poured concrete between them, then nailed the wood floor to the 2x4's. Has anyone seen that done? In this area, the concrete is not smooth at all and I was wondering if I could frame out and pour my footings on top of that. I can use as many jack posts as I need. I thought that would help also on the thickness of the footings if the posts were placed closer together. Is that correct or am I way off base?
One other thing is that on the first floor (on one wall that I will be jacking up) there is a french door with two side windows that only has cripple studs over it. I'm assuming if I don't want to crush this door I should probably put in a header. Am I correct?
Sorry so long & thanks for any suggestions.

 
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03-18-06, 01:00 PM   #2  
You have a big problem here, and I have already read your post 3 times and am now digesting it. I have jacked up alot of 2 story houses from that era including mine. They are all different, and non of them easy. I will get back with you soon.

 
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03-18-06, 07:08 PM   #3  
Thanks for the reply Jack.
I'm new to this forum but have been reading archives for quite some time! I will get some measurements for you to try to make this a little clearer. I am not expecting to get the floors back to "level" but feel that if nothing is done, this will only get worse.
I have removed most of the plaster on the upper floors to remove some of the weight and I am cautiously optimistic about giving this house a new lease on life! (husband shakes head here!!)
Have you seen that done in a basement for wood floors where they lay down 2x4's and pour concrete between them to anchor? That was really interesting.
Thanks again and let me know what info you need.

 
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03-19-06, 05:30 AM   #4  
Two questions: What is the unsupported span of the floor joists? What part of the country do you live in ?

 
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03-19-06, 06:42 PM   #5  
Ok
Imagine a 34 x 34 and in the basement is a cement wall running North-South 17 feet from the east wall. The load bearing wall upstairs is 13 feet from the east wall. The floor joists are 2x10 16" O.C. and run East West the entire length of the house. The other wall needing jacked up is running E-W on the West side of the concrete wall. Obviously there are no perpendicular joists under this wall. It is approximately 3 feet off of a framing wall that is under part of the 2nd story staircase. The walls above this are the french door wall on the first floor and a bedroom wall on the 2nd floor.
The joists over the first floor (2nd floor) are 2x8's 16" O.C. also running East to West.
I am in southern Kansas.
Thanks for your help.

 
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03-22-06, 11:12 AM   #6  
Jacking up the House

Sorry I took so long to get back to you, but there is a lot to think about in answering you.
Before tackling this project, there are several areas that you must give some considerable thought to. Only after you are comfortable with each area, should you procede.
The first thing you must remember, is that you have a big, tall heavy house. A very heavy house. I always tell people that when you go to jack up a house, you must always think up. Remember, everything will move up to some degree. The first floor, the second floor, the attic and the roof. So you can see, you are not just jacking up the floor joists.

The second thing to think about, is that this will not be an easy job. It will be a hard job, it will be a heavy job, and it will be a long job. All of your materials must be taken into the basement. Tools, concrete, water, beams, posts, jacks and much much more. None of these items are light. They are all heavy. Can you get you beam into your basement ?

The next area is time. This is not a day or weekend job. This job could very easily take several weeks. Once you begin, you can only jack up your beams about to a maximum of each time. You jack it up and you let it set for several days. Then jack it another . You can see what I mean about time. Each time you jack it up you must hold it in place. So you are constantly resetting your posts.

The next area is your footings. They must be very strong. I recommend a 12 square, and 12 deep minimum with rebar. You will need a footing at least every 5 feet. In most cases you will need double footings. Footings for the jacks, and footings for the posts. Without good footings, you are wasting your time. To lift your joists with the amount of weight on it that you have, you will need at least 4 20 ton hydraulic jacks. You will need a jack at least every 5 feet. You will have to set you jacks on posts or build piers. Piers are the least dangerous. On the top of each jack you will have to have a cap. They are made of plate steel thick and they are about 4 square. You will have to have them made. They go between the top of your jack and the wood beam, otherwise you will pump the head of your jack right into the beam.

The next area of grave concern, is the danger of this type of work. This is very dangerous, even for the pros. The big danger is a post kicking out, or a jack kicking out.
This will happen while your working with them. There will no warning. It will happen in a split second, and there will be no time to move out of the way. Recently while jacking up a house like yours, we had lifted the house about 3. Everything was going fine. I had 3 jack men. I would say how many pumps to make before stopping. We had stopped and were almost ready to begin again when I hollered to get out of the way.
They barely had time to move when a jack and a post kicked out. One of my men barely escaped serious injury. They asked how I knew since there was no warning. I told them just a sixth sense, from years of experience. Just a chill down your back. It can happen that quick.

Now, I want you to read this over very carefully, and discuss it with each other. If you are still intent of doing this answer back and we will go a step further. Good Luck

 
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03-23-06, 04:28 PM   #7  
Hi Jack,
I appreciate your thoughts very much. The good thing is that I am in a farming community so I have access to steel plates, jacks, etc.
We also have an entry to the basement from the outside so getting tools and the beams in should not be a problem. I had originally thought we could use jack posts but since reading your post I guess they are probably not to be used to jack up that much weight. Also, when you say after jacking up you reset the posts, that means we are using adjustable there...correct?
What is your normal set up for the jacks starting from the base?
Would a steel I-beam be better than the laminated beams?
Thanks so much for your time and thanks for the warnings, they were not taken lightly but I do think this is something we can do.

 
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03-24-06, 04:53 PM   #8  
Yes, the post jacks are used when you reset the posts. After you jack up a little, you just screw the jack up tight. I think I would use lam beams. Probably two of them and bolt them together for a greater width. I kind of lost what you meant by saying "the normal set up of the jacks beginning at the base." My brain is old and tired. Let me know.

 
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06-16-07, 09:11 AM   #9  
jacking up your house

Iwould recommend before lifting any thing ,to start by picking up a reasonably priced lazer made by (black & decker cross fire )that when set up in the basement will display a line on all 4 walls and if it is placed along the center of the home underneath the beam and left there you will be able to get readings throughout the basement to first decide where the low spots are ,and how much of a difference there is. Once the lazer is set up measure up to the bottom of the beam your lifting in several spots and on each beam that is there, i am working on a home that has 3 beams in the basement so grades have to be marked on all of them.I have been lifting a 2 1/2 storie home that sank 3 1/2 `` all across the front of it, and i have been working with nothing but screw jacks mostly 24 ton ea but i have two 35 ton jacks under the center beam where it came into the front wall. Let me tell you you will be lifting serious weight here, (everything in the house take a look around in your house on each floor)and then think about lifting it all at once.Be careful
Big Jax

 
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