Posted: 10/16/2012 7:42:54 PM EDT
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I'm working on changing some rooms in my house from carpet to hardwood. Step one, I tore off the carpet and pad, removed the moldings, and then started checking the floor for flatness. Well, lucky me, I have a "trench" in my floor, middle of the room is 1/4 to 3/8" low. So I go in to the basement... and it turns out that the nearest joist to the low spot is so bowed you can clearly see it just standing there. I think it must dip down 1/2" in the run between the wall and the steel i-beam it is resting on. Is there any issue with just shimming the subfloor along the bowed joist (and some at the neighbors) to even out floor? I don't need to put a jack under that thing, do I? |
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I don't know... that's why I'm here asking! There are a pair of cross braces between the joist and its neighbor. I guess I could knock them out, put in a straight joist next to the bowed one at an angle, and then bang it vertical with a big hammer? Is that realistic? Quoted: Any way of installing a new floor joist next to the existing one and adding pressure to the new one to help push against the sub floor? |
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Quoted:
IMO you need to sister a new joist to the old one and jack it level. Use glue and screws. Probably have to reinforce the joists on both sides of the bowed one too. What length and size is the bowing one? sistering a new joist or shimming should be ok. use glue on the shims so they dont vibrate out. Also use screws instead of nails. Make sure you have min two layers 5/8" ply wood for your sub floor. Many contractors use particle board for a top layer under carpet to save money. |
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Quoted:
LOL. It creaks like crazy now. I was hoping I could put some fresh ring shank nails into it to snug it up and make it quiet. Will shimming it make it creak more? Quoted:
Are you willing to live with a creaking floor? Use actual screws instead of nails (of any type). And NOT drywall screws. Their hardness weakens them and leads to fracturing. |
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You aren't in bad shape. Especially with access underneath.
Pop that subfloor up into level, big hammer, digging bar, whatever. I prefer digging bars for ease. You will need someone up top to tell you where to go and when to stop. Up top, use a few strings nailed to the high spots, bridging the low spots. You don't need to go crazy here. If you start moving things that don't need to be moved you will drive yourself nuts later. Next is the joist sistering thing. You NEED to use construction adhesive (subfloor variety). Don't be shy, buy the big caulk gun. Use it on the top and the side of the joist you are sistering. Use nails to sister the joists together. Nails have a much higher shear resistance than screws. Use deck screws to screw the subfloor to the new joist. There are other screws that are perfectly acceptable, but in the big box stores, deck screws are the easy way to know you've got the right thing. Once you are done stay off it for 12-24/hrs. Subfloor adhesive will dry very hard and act as a shim between gaps as well, as long as you don't keep walking on it. Next step is hunting down the rest of the squeaks with the deck screws. Often the blocking between joists are the culprit. You have to decide if your floor has enough deflection to warrant an extra layer of subfloor. It sucks to be wrong here. Either you have a bad joist or two, or your framers didn't know how to crown their lumber. Either way, the problem you have is an easy one. |
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"Check the size of the member", good thing this isn't GD. I think the joists are OK, the couple that bowed are not under much load (just holding up living room floor). They're 2x12's, I think. Quoted: The real question is - did the builder overspan his joists? Check the size of the member against a span table to ascertain. If the joist(s) are over-spanned, you're in for more trouble when the rest of the joists start sagging too. |
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What type of underlayment do you have? I see you had carpeting, so a lot of home builders used particle board underlayment for many years when building homes with carpeting. I just installed 3/4" hardwood flooring in two rooms in my home and I had to rip out the particle board underlayment before I could install the flooring. I'm asking because you said that the floor squeaks like crazy when you walk on it. Mine did the same thing until I pulled out all of the underlayment.
The other guys above me have given good advice on how to correct the sagging floor joist so I won't go further except to say that if you are installing hardwood you need a flat floor to install it on. The prep work you put into it now will prevent you from ripping it out later to correct the squeaking and sagging problems later. |