Floor sag

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  #1  
Old 01-02-15, 07:57 PM
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Floor sag

So I figured out why my living room sags and my dining room sags. The sag is about 1/4" to 1/2" about 4' from the wall. This is what I have found by looking into a basement area where you can see the floor joists. The joists are good, but what they are sitting on is odd. There is the beam. It is a big one, like 4x6 or 4x8 big. But on top of that is two 2x4s laid on top of each other. Then on top of it is 1/4"x something thin board. That thin board is cracked in spots where the sage is the worst. Jacking the beam would do no good as it appears the joists need to be jacked in order to replace that small piece of wood. I am not sure why it is there.
Thoughts?
 
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  #2  
Old 01-02-15, 08:33 PM
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It doesn't sound like the 2 2x4s on top of the beam are original since the house was built. Can you determine if that is correct or not?
 
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Old 01-02-15, 10:15 PM
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It sounds like that sag is a little far from the wall for that 1/4" to affect it. Can you shoot a picture or two of your structure there. http://www.doityourself.com/forum/el...rt-images.html
 
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Old 01-03-15, 11:31 PM
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Okay... I am wrong.
here is what is actually going on.
I am not sure about the 2x4s on top of the beam, but they all appear to be original. However, the sag in my living room is from undersized joists. I have 2x8s 16" center spanning about 13'. In the middle are x braces made from wood. But my living room has a noticeable bounce and has sagged. At this point I am not sure how I am going to fix this as there is tons of electrical and HVAC work in this floor that would have to be moved. If I added something to the bottom of the joists I would lose headroom and right now my lower ceiling is at 7'
6".
 
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Old 01-04-15, 04:39 AM
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We are very visual people. Remember you can see it, we can't.
 
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Old 01-04-15, 05:25 AM
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If the joists are in fact bowed/sagged with a low spot in the middle I would jack the floor and sister the joists for their full length.
 
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Old 01-04-15, 05:29 AM
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That would be the ideal solution but it doesn't sound like there is enough room to insert joists.
 
  #8  
Old 01-04-15, 09:59 AM
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All my cameras got stolen when I got robbed a few weeks ago.
So pics are not possible.
let me ask you this though.. when someone bounces upstairs the downstairs ceiling (the one below the living room) shows visible deflection.. scared my wife the first time my son jumped and the whole ceiling shifted down and shook a bit.
Is that normal?
 
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Old 01-04-15, 10:35 AM
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Name:  Joist and Support.jpg
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I forgot about my crappy work phone camera.. so here is a pic of where the floor joists hit the main beam and it's 2x4 toppers.
 
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Old 01-04-15, 11:51 AM
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Nothing there looks crushed or rotten. I still think full length sistering is the best option. It's a structural job so I would not put it in the "minor" or "quick and easy" category. Does your wiring pass through holes drilled in the joists or are they stapled to the bottom of the joists?

If your wiring is stapled to the bottoms you can pull the staples and probably get enough room to slide in the sister joists. If your wiring runs through the joists they may need to be temporarily disconnected and pulled out if possible. Another option is to cut the wires, do the sister repair work, then repair the wiring with junction boxes at each end. A third option would be to install a beam down the center of the room underneath your sagging joists. A beam though would require columns which I'm sure you don't want.
 
  #11  
Old 01-04-15, 11:59 AM
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No, it is not normal for the entire ceiling to shift. I would install some lolly columns, in the cellar, for now.
 
  #12  
Old 01-04-15, 01:12 PM
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This might require a pro.
 
  #13  
Old 01-04-15, 05:40 PM
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I just went into my basement and measured my living room framing above it. My span is 13-1/2' from the rim to the center support beam, 16" O.C. The floor joists that I thought were 2x8 s actually measure only 7". This house was built in 1959. I don't get any bounce in my floor. It looks like tongue and groove underlayment with hardwood on top.

What is on top of your joists ?
 
  #14  
Old 01-04-15, 05:47 PM
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I have 3/4" plywood with an overlay of 3/4" particle board. I had my son and wife walk around while under the room and there is no deflection. Only if someone heavy jumps do I see the ceiling shift around where they jumped. I note that I can feel people walking when they are roughly on the joists or nearby joists. I wonder if blocking to help spread the load would help or more xbraces. My floors only have on in the middle. But it is missing where the hvac pipe goes. But in the end sistering is probably my best options. Also only the living room exhibits this. I wonder if it is because this is the only room with that long of a span.
 
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