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Floor seperation problem

whois | Posted in General Discussion on July 31, 2020 10:20am

House was build in 94, two story cape.  On first floor, cracks in ceiling, gotten worse over the years.  Recently took up carpets upstairs (probably was put down to hid crack, when house was constructed).  Crack in floor, the length of the house (30 Feet).  On outside walls is 9/16, in center (where stairs are), 1  and 5/16 inch.  One side of split higher than other (poss 1/4 inch).   This is basically where the center beam in the cellar of house is, but nothing appears to be wrong in cellar.

Various thoughts on how to fix.  Sand down and seal the crack (not sure that this will prevent further cracks).  Or, cut back the floor, on both sides of crack (a foot or more on each side), and put down new floor (nailed and glued), to better hold bother sides together (probably will still need some sanding to get level)…or what?  See attached image.

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Replies

  1. User avater
    unclemike42 | Jul 31, 2020 04:15pm | #1

    It sounds to me like your framing is moving.

    the roof could be pushing the walls apart, and nothing is holding the second or first floor flooring together.

  2. Frankie | Jul 31, 2020 07:55pm | #2

    Are the joist parallel or perpendicular to the joists?
    Same question for Roof ridge.
    What does the joint expose?
    Crack in ceiling below the same dimension?

    Frankie

  3. sungod | Aug 01, 2020 11:08pm | #3

    Sometimes cracks appear when the joints in plywood or drywall did not have staggered joints.

  4. User avater
    unclemike42 | Aug 02, 2020 06:11am | #4

    So I would take a closer look in the basement, and make sure those floor joists are joined to each other where they sit on the central beam. if not, make them do so, structural screws or liberal use of a framing nail gun should help. (if the joists overlap at the joint)

    if they do not overlap, then a metal joint, or sistered wood joist can help.

    Try to get in the attic, and verify the same thing.

    and apply the same remedy to keep the ceiling joists from moving further apart from each other at the central joint

    once you get the framing to stop moving, patching and cosmetics can be done without fear of an ever-returning crack.

  5. jlyda | Aug 02, 2020 09:30am | #5

    You sure there is a crack? From the pic (hard to see clearly zooming in close) it looks like they changed direction of the subfloor and sheets were installed tight to the tongue. The tongue should have been cut off, so sheets could be installed tight. It looks kind of strange that they would change direction of the subfloor (and possibly joists as well), but you do often see a change of direction of joists in more cut up homes. Without knowing the story with all of that it’s hard to tell, but structural you may be fine. Do the cracks on first floor line up exactly where the seam is?

  6. Geoffrey | Aug 02, 2020 11:46am | #6

    That is NOT a "crack" in the sub-floor it is simply a space that was created when they changed the direction on the sheathing. The left side is running vertically or top to bottom, the right side is running horizontally or right to left due to the fact the joists are running in perpendicular directions on each side of the beam, just fill the gaps with some strips of plywood and leveling compound and be done with it.

    Geoff

  7. whois | Aug 03, 2020 05:46pm | #7

    Starting from the top, I will reply here.

    I am a computer person. I can do some wiring, some plumbing, sheetrock (but not the final coat), but I am not a home builder. The house was built in 94, I bought in 98. There were some cracks in the first floor ceiling, in the hallway entrance, and living room entrance, from the kitchen area at that time, but it was attributed to house settling. I did initially cover then up with mud, but over the years they reappeared and got worse. Upstairs was covered by rugs. Those ceiling cracks follow the split upstairs.

    The walls are not being pushed apart, there is no bowing.

    As noted in later posts, the subfloor was put down in different directions. In the image, on the left side, the subfloor runs parallel to the crack\split, and thus the joists are perpendicular, nailed at 16 inches. On the right side of the split, the subfloor is perpendicular to the split, and thus the joints run parallel to the split, and are nailed every 12 inches.

    In the basement, the floor joists are joined to each other. The basement ceiling is not finished, and the first floor joists are placed the same as on the second floor, where the split is. The joists in the attic all face the same way, perpendicular to the split below.
    “ but you do often see a change of direction of joists in more cut up homes. “ Not sure what is a “cut up home”, (additions or a house that is not square?). I imagine that this house was built entirely at the same time.

    In one room, putting a level down across the split, in three different place, gets three different findings, the middle looks good, one is high on one side of the split, the other is high on the other side of the split. The middle of the house, where the stairs are, is slightly off. The other room (where you can see the edge of a bed), is about ¼ higher on the left side of the split. It is not just that it is higher where the split is, but that that side of the house is lower (I put the level on the subfloor on that side indicates that side).
    There are no cracks in basement walls, so nothing to indicate that the house is setting.

    The first floor ceiling cracks have gotten worse over the years. I am not sure that filling in the split, sanding down, leveling, etc., is going to stop the cracks from getting worse, or reappearing again (If I again mud the ceiling). If the subflooring was all going the same way, perhaps cutting back the subfloor on both sides of the split, and joining both sides of the split with new subflooring might keep it from splitting more….but not sure if this can be done. Then downstairs, also cut back the ceiling where the cracks are, take a foot out, put ¼ inch plywood (for additional holding together of the split), and then ¼ inch sheetrock.

    I have attached 1 image here (could attach a series of images from basement, to ceiling cracks, and more of the split), but it would be 25/30 MB. I will attach 1 image with the reply. It is the center (where the stairs are). In an additional posting I will attach an images from the room with the bed, and it is total different in that you do not see a joist going across the split, and you can actually see into the floor.

    1. jlyda | Aug 04, 2020 06:31am | #9

      What I’m referring to as a “cut up house” is that there are a lot of ell’s/bump out’s etc within the design of the home.

      I do think it will be hard for anyone to troubleshoot without walking through the structure. If an addition or alteration were performed by previous owners it could be that there is a discrepancy where the new work ties into the old. If something structurally is going on do not invest any $ trying to make things look better as it will be $ wasted until you correct the issue. It may not be a structural issue. Could be that the lumber was really wet when installed and has shrunk/settled from drying out. I would encourage you to seek out a contractor or engineer with a good understanding of structural issues to see if they can offer some advice. They need to walk through and see what all is going on.

  8. whois | Aug 03, 2020 05:47pm | #8

    Here is the second image...

  9. starrjack | Aug 08, 2020 08:54am | #10

    I think this is not crack,this looking like a gap plywood or drywall.

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