Leveling floor joists

Discussion in 'Remodel Forum & Blog' started by draven8795, Apr 7, 2013.

  1. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    Doing a full bathroom remodel. I've ripped out about half the subfloor to replace rotted plywood. I'm thinking of ripping the rest out now because the floor is so out of level.

    From the outside wall to the interior wall the joists are almost an inch out of level over 5'. The house is obviously sloping inwards.

    My plan was to use 2x4s and cut them to correct the slop and glue and screw them to the existing joists to get them back to level running the length of the joist. My real question is how do I make sure that the perpendicular is still level (or just close to level doesn't have to be perfect) so when I put the new subfloor down i don't have heaves and valleys.

    Just get everything closer to level so its not so drastically out of level and then use a self leveling compound?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,679
    Location:
    Cave Creek, Arizona
    Use 2x6s and secure them to the sides of the existing joists with the tops level.
  3. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    Yea that was actually my next bit i was going to think about. Can they be glued and screwed to the other joists or do I need to put a bolt through a few spots?
  4. kreemoweet

    kreemoweet New Member

    Messages:
    371
    Location:
    Seattle. WA
    Glue&Screw is fine. Find the highest point on the existing floor framing, and set all your joist scabs level with that. A horizontal
    laser makes it all EZ.
  5. Terry

    Terry Administrator Staff Member

    Messages:
    15,038
    Location:
    Bothell, Washington
    You can pull strings across the floor and bring the new joists up to that level.
    Or a laser level.

    You may want to look at jacking up an resupporting too. I had a home that had dropped in the middle. I went in the crawl space and saw that the original framers had not used all of the concrete pads under the stairwell. I moved those into place, rented some floor jacks and lifted things up, and resupported them. Doors that hadn't closed right before now worked.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,051
    Location:
    New England
    If you want to jack the wall up, do it slowly over several days or you'll crack things (well, if they'd already cracked, those may close!).
  7. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    Thanks for the info guys. Since the house is sitting the way it is I think I'm just going to leave it alone as far as trying to jack it up. I'll just tear out the rest of the subfloor and go get some 2x6s. Once this is done the project should hopefully start flowing again.
  8. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,248
    Location:
    Land of Cheese
    If you plan on laying tile you should go bigger instead of smaller to reduce the deflection in the joists. Construction adhesive and lag screws like Spax are your friends.
  9. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    Because I knew the floor was going to be out of level we decided in vinyl flooring even before we started. Then after taking some more precise measurements I realized how really out of level it was.
  10. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    One last question should I put the screws in from both sides (old joist side and new joist side) any sort of limit like X inches a part?
  11. draven8795

    draven8795 New Member

    Messages:
    37
    Location:
    Wisconsin
    Well the sistered in 2x6s are almost complete the next question is the transition from the bedroom is an inch and a half of subfloor made up of a 1/2 inch plywood covered with with 3/4 inch particle board with fairly thick carpet on top

    To get the the transition height from the bedroom into the bathroom close should I just use 3/4" plywood and then put another 1/2" sheet of plywood on top of that with more gluing and screwing so it doesn't squeak?
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,051
    Location:
    New England
    If the first layer of ply is installed properly, it's safer to not glue the second layer to it. If you decide to do it, you need a liquid wood glue like Titebond II, a trowel to spread it around so you get full coverage, and lots of screws and be fast about it so you get it spread and the second layer down before it skins over. DO NOT use a construction adhesive or you'll be creating problems as it's nearly impossible to get 100% coverage. Construction adhesive on the top of the joist works because the joist is only 1.5" across, and it's not that hard to get enough force to get intimate contact. You can't do that with construction adhesive spread over the whole sheet. Regardless, when installing the second sheet, do not line up the joints with that below. In fact, run the end 1/4-span past the joist (on 16" OC, the end should be 4" off the joist center). The whole goal of the second sheet it so cover the first layer's end joints on the joist and isolate the minor jacking caused by deflection mid-span...1/4-span is the ideal distance to minimize that. In your case, unless you're planning natural stone (which would require the second layer of ply), you're doing this more for height verses strength. Just screws (NOT into the joists) is sufficient to keep the layers intimately attached, assuming you use enough in the proper spacing. You then have a choice of cbu or a decoupling membrane on top of the ply before you tile. The decoupling membranes available are thinner than cbu for the most part (DitraXL is an exception and is used rather than Ditra when you need extra height). Membranes, in my experience, are a lot easier to cut, carry, and install verses cbu - just thinset to install, and it cuts with a sharp knife or scissors. You can carry all you need for a big room easily on your shoulder, and it works better! Also, if you seal the seams, it's waterproof, should that be of interest.
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