Repairing floor sagging


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Old 07-24-11, 08:19 AM
J
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Question Repairing floor sagging

Hi all,

For my first post here I hope I can describe this situation well enough. The basic question is about the best strategy for jacking-up a low spot in my floor

We're putting new engineered hardwood flooring throughout the 1st floor of our 15 yr old 2 story house with a crawl space. After removing the carpet from the dining room, where we'll start laying the floor, I discovered a "break" in the floor. i.e. a point where the floor abruptly starts to drop. In the 4 ft from that point to the wall it drops as much as 1.5 in. This is in the East direction. In the N-S direction the floor is level. And West from that point the floor is level. My spirits really sank at this discovery.

After I recovered I continued investigating. Continuing in the E direction from the dining room thru a doorway is a short ~4 ft hall leading to a 3.5 ft wide N-S hall running most of the width of the house. Continuing thru the doorway, removing carpet as I went, to the opposite wall of the hall the floor is pretty level although ~1.5 in below the level of the dining room. Also from about 15 ft north of this point along the hall the level drops about 1 in.

So now into the crawl space I find a beam in the N-S direction right under the break in the dining room floor. The main ~50 ft long N-S beam is about 12 ft East. This has 3 evenly spaced concrete block piers. The middle one has some wood "spacers" on top of it and this is about at the low point of the floor I measured. The beam runs under the easterly wall of the hall, also supporting the main N-S 2nd story wall.

So, I think I need to add another ~1.5 in. spacer on top of that middle pier and maybe some on top of the other two. But I also have to consider the fact that the floor drops 1.5 inches in the first 4 feet but then doesn't drop much more 'till I reach the main N-S beam. What will happen to that when I raise the floor at the main beam? Do I use some kind of screw jack to raise the floor to put in the spacers? How fast can I raise this 1.5 in? The new 5/16" flooring will run N-S. Can I nail down the flooring before the leveling process has been completed?

Thanks very much for the help,
Jim Greetham
 
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Old 07-24-11, 11:28 AM
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Oops - I said there are 3 supports along the main but there are 7. 6 original ones and a 7th which was added when we bought the house 12 yr ago to fix a problem with doors not closing properly.
 
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Old 07-24-11, 05:19 PM
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Jim, welcome to the forums! At first reading, my main concern would be the other room at the lower level. Was it intended to be that way from the get go? Has the entire other room settled? It's gonna take some investigation from under the floor to determine if the outer sill has failed or if the room was built on after the main structure and the floor levels were different, causing the flooring to be installed at a slight angle.
I'm with you, don't install the flooring until you get the subfloor level.
Take a few pix of what you have and let us see what you see. We may have an idea or two for you. http://www.doityourself.com/forum/el...your-post.html
 
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Old 07-24-11, 05:46 PM
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It troubles me that a home of this age has such a severe problem with the floor. Sounds like there is something very wrong here to me. Especially if you bought it when it was 3 years old and had to jack the house so doors would close. Dig deep on this and try to find the root cause.
 
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Old 07-26-11, 06:16 AM
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Thanks for the insight. Investigation is continuing. However I had a disruption last night when my dishwasher started leaking around the motor. So the extra $900 that was going to go on the flooring payoff has a new purpose. I've also thought that I'll get out my laser level so I can check what's going on over longer distances. More to follow...
 
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Old 07-26-11, 05:34 PM
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Well, let's see if we can make some sense of this:

We have a rectangle 5 x 7 paces with corners W, S, E, N. There is a stairway inside the rectangle which turns 90 deg about half way up. The W-S side is 7 paces and lies along the dining room beam. The E-N side, also 7, is along the main beam. The W-N side, 5 paces, points out of the dining room and toward the back of the house thru the kitchen. The living room is outside the rectangle on the S-E side.

Based on my laser level measurements, corners W & S are at 0. Corner E is -.75" and corner N is -1.5". The center of the house is about half way from E to N.

It seems to me that I need to jack up corner N by 1.5".

However, the kitchen and living room are pretty level now. Well, maybe not level but at least flat.
So if I jack up the N corner it might make the kitchen floor twisted.

Additional info is: My wife informs me that the house was built in 1987 and we bought it in 1997. This is north Alabama with very rocky red clay.

Cheers,
Jim Greetham
 
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Old 07-26-11, 05:44 PM
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Just west of Sand Mountain, huh? I'd hate to dig water line trenches over there!
If you jack one corner up, what will you do with the adjacent corner? It is sagging by half that much. Really, go under the house to find out why this is happening. There's gotta be a reason, whether it be rotted sills, sagging footings, improper piers, etc.
 
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Old 08-21-11, 03:11 PM
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Hi all,

Back again after a trip to the beach and some more investigation.

We had a foundation guy come out to give us an estimate for a fix. I'm enclosing a floor plan he drew with some pertinent info. I'm using Dropbox - hopefully it'll be OK.

The dining room where we discovered the problem is at the front. Notice it's not quite to scale. Anyway, he says the floor joists deflected because of the weight of the stairs & 2nd floor. So he wants to put in the indicated new beam & supports. In the estimate, he doesn't guarantee that the floors will be level nor that any wall cracking will occur. About the only thing he guarantees is his work & materials. So, what IS he going to fix?

Note that this span between the 2 existing girders (trippled 2x12s) is only 10 ft. with 2x10 floor joists 16 in. o.c. And half the stairs are in a 2-story foyer so there's no additional weight to support there.

I also put in some of the level measurements at some points - these are the numbers double-underlined. The numbers are the distance from the level to the floor so a smaller number means the floor is higher. It looks to me like the house was just built on 2 levels - the front is 1.5 in higher than the back.

Thanks very much for your continuing help.
Jim
 
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Old 08-21-11, 04:55 PM
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However, I just took a look in the attic and the roof framing looks to put a lot if the roof weight on the wall midway between the 2 existing girders and over the proposed new one. I wonder if I could put in some additional support leading down to the wall above the main girder.

Cheers,
Jim
 
 

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