Joists & Leveling Floor....

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Old 09-10-13, 08:09 PM
K
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Joists & Leveling Floor....

Hey All,
First house and new issues. A little back ground about the house, it was built in the early 70's, single story home, 2200 sqft, full basement / garage thats unfinished and a small addition on the side with a crawl space underneath that was built in the early 90's.

My floor is a wave from one side of the house to the other. Its interesting trying to walk over it after a night out with the wife and a few to many cocktails. You can see where someone has previously tried to sister the joists in random spots and there are random floor jacks in the basement supporting the sub floor that seem to do no good. Where Im struggling is where to pick my spot to level the rest of the floor out with. The HVAC runs right down the middle of the house (length wise) so I cant hang a line from one side to the other (width wise) and measure from that. I've got a section about 8' that I ran a leveled string from nail to nail and I've got 11.5" from the underside of the sub floor to the string (center of house) and 11.15" at the foundation wall. So I have a significant drop, or raise going on? How do I figure out which end is the right height? Wound I measure from the basement slab up and hope that the slab is true?

Thanks in advance!

Kelly
 
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Old 09-11-13, 04:00 AM
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Kelly, welcome to the forums! From your description, and jacks in the basement, it sounds as if someone has already tried, unsuccessfully, to fix the problem. Would it be possible for you to post a few pictures both from above the floor and in the basement showing the problem areas. No close ups, please. We know what nails look like . It may help us give you better advice. http://www.doityourself.com/forum/el...your-post.html
 
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Old 09-11-13, 06:16 AM
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Leveling

A laser level would help. You could borrow, rent, or buy. Measure from the laser beam to the bottom of the sub floor. Is your foundation level?
 
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Old 09-11-13, 06:38 AM
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Slabs are never flat or 100% level, there useless to use as a reference point.
I use a self leveling lazar level when doing tis job.
Johnson 40-6516 Self-Leveling Rotary Laser Kit

When I have to work on a home that old what I often find is someone at some point has removed supporting walls in order to do the in thing of "opening it up".
Moved or removed supporting columns in the crawl space or basement without taking into consideration they were put there for a reason.
Major support structures cut by the HVAC or plumbing trades to make there job easier when running lines, without taking the time to header off and lost strength.
Insect and moisture damage.
Over spanned and under sized joist.
It would be great if you could find someone that knows what there looking at to look this over and take in the big picture not just try and prop up a few areas.
 
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Old 09-11-13, 07:17 AM
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The first step might be to find what you have now. As already mentioned a laser level would be the best tool to start with though you can also use a piece of clear hose/tubing filled with water. I set up the laser level at an easy elevation about shoulder high for me and walk around with a tape measure and put the tape up to the bottom of the joists and work around the house drawing out a little map with the elevation. The exact numbers are not important but the differences are what you are looking for.
 
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Old 09-11-13, 07:36 AM
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Maybe your numbers are a typo but 11.5" - 11.15" = +/- 3/8" which doesn't sound like a whole lot for a 40 year old house. In any case, if you can't use a laser level, google "water level". Basically a long length of clear plastic tubing filled with water. It's not the fastest way to go but it let's you mark a level point around obstructions, corners and through doorways into other rooms.
 
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Old 09-11-13, 01:52 PM
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Hi All,
Thanks for the replies everyone. After looking closer today I saw a few different spots where old jack posts used to be that are no longer there as it looks like they were initially held by the concrete slab and were removed. Some of the newer posts are within a few feet of them but there is some obvious spots where posts should be.
Joecaption1- that laser level looks sweet but I cant throw down $600+ for it. There was another around $100 that would be doable though. Is the idea behind the laser level to set it and measure from the bottom of the floor joist or the underside of the sub floor as I can access both because the basements unfinished to where the laser hits it? Record the height and then raise or lower the floor as needed?
My dilemma is how to figure out what height to go with? I measured the opposite side of the room exactly how I did it the first time and my measurement was about the same with a peak in the middle, so 11 outer to 11.5 inner. This would lead me to believe that the center section of the house is being pushed up as both the sides are pretty close in height.

Thanks All!

Kelly
 
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Old 09-11-13, 02:58 PM
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Rotary levels are fine for building decks, and that is what I use, but a PLS, or dual line laser really is compact and throws a solid horizontal line and solid vertical line, and is self leveling. My Bosch cost about $116 at HD. You will find numerous uses around the house for one, so investing is a no brainer. Placing pictures in a hallway, etc.
 
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Old 09-11-13, 09:43 PM
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When you take your measures, take measures where the joist is near the foundation wall and where the joists are at a support beam. They should be the same, if not, the beam may have shrunk or settled over the years. If needed, then jack the beam up so it is level with the foundation. If these are level then go to the middle of the joist (between the foundation and the beam) and see if a joist has sagged or is jacked up. If the joist has enough sag, you could sister another joist to it to help keep it up. I also would take a 4' or longer level or straight edge and place it perpildicular under the floor joists to check that all the lumber is the same thickness. I have seen 2x10s ranging from 9 1/8 to 9 1/2" in thickness and this could make you think a joist is sagging by 1/2" when it's really not.
 
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Old 09-12-13, 06:59 AM
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Leveling

Ultimately, you will need to find the highest point on the supporting foundation. Everything will need to come up to that elevation since you cannot lower the foundation without doing "major surgery".
 
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Old 12-10-13, 07:40 PM
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Hi again-
So I've had 2 estimates for leveling out my floor and replacing 1100 sq ft of 1 1/4 particle board ( 2 each 5/8 layers sandwiched) sub flooring to the tune of $11k to $15k. Being stubborn and not having a trust fund Im going to under take the project on my own and hopefully have it done in 2 weeks working days off and nights starting the first of the year. Oddly enough my biggest worry isn't leveling out the floor anymore, it's all the wiring and duct work that runs through or in parallel with the floor joists that I'll likely be sistering or replacing. Should I notch the joists if I can or pull and run new wiring? Whats the maximum depth I can notch a floor joist and not compromise it? Ive also got two 5 foot long load bearing walls that hold up my vaulted ceiling that will be interesting to work around. Thank you everyone that contributes to this website, it's much appreciated.
Thanks
Kelly
 
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Old 01-09-14, 07:08 PM
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Angry NOOOOOOOO!!!!!!!!! Do NOT notch your joists.

Do NOT notch your joists. Other than cutting through them, it is the next worst thing you can do.

Drill as close to center as possible and look on line to find a table with the max size holes and spacing based on joist size.
 
 

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