Need some advice… In order to eliminate a 3/4″ dip in my kitchen floor, I sistered a new 2×10 on to an existing joist that had cracked almost through (top to bottom) due to two large knots in the joist. The fix eliminated the dip in the subfloor due to the cracked joist, however, now I have a hump at another location on the floor along the joist. Due to the failure, the existing (old) joist has a wave in it (from + ¾â€ to – 3/4â€) as it runs the length of the span (approx 14’). When the old joist was jacked to remove the dip, the high point of the joist pushed the subfloor upwards approx ½â€, causing the hump. The question I have is how do I get rid of the high point on the old joist, or more accurately, how do straighten the joist so that it is in line with the new (straight) joist. Any tips/tricks would be much appreciated!
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Could you remove the old joist altogether and replace the 14ft span?
I've thought of that, but I'd like to avoid it if I possibly can. I was thinking about wrapping a piece of angle iron around the new joist so that one leg lies below the high point on the old joist and then driving a lag through the angle iron into the old joist (from below)...any thoughts or and tricks from any of you guys out there?
not sure how I'd fix it w/o looking at it ....
but ... is the finish flooring gone and we're standing on the subfloor now?
cut the subfloor back to the next coupla joists for a coupla short feet ...
power plane ... or block plane ... or belt sand .....the offending wood flat ....
replace the subfloor.
Jeff
Buck Construction
Artistry in Carpentry
Pgh, PA
swiss.. i ass_u_me you have access to all of the joists from below
start by running some string lines so you can determine what is in plane and what is not..
you think the new sister is straight.. but it might be severely crowned
or you may have jacked the split joist beyond the true plane.. you might have to let it partially back down
if you string and block in several directions you can get true measurements ...
> if you string and block in several directions you can get true measurements ...
Or you could use this as the perfect reason to get one of those really cool laser levels that can cover the whole plane in one setup.
-- J.S.
Best advise I can give from dips in floors, (ESPECIALLY after jacking), is getting the string in there from all points to see EXACTLY where the problem is before trying any remedies. Joel
Pile drywall on the high spot, about 4 feet high. Leave it for a month or two. That'll lower it right down.
Mike Smith and others have, as usual, chimed in with good advise.
To paraphrase: find out where you are before you set off.
Anyway, once you have put up a stringline (all you really need), and detirmined which joist is errant---cut it in the middle vertically with a skillsaw or whatever.
You won't have to go right through. Leave an inch or two. Don't worry.
The house will not fall in on itself.
We're talking about the high-crowned joist here-right?
Any way if it doesn't drop of its own accord, get someone to jump on it from the top. Have a slender shim shingle to push into the kerf. This will hold it.
The final step is to nail on a sister joist to the original. Try and get the ends within a couple feet or less of the original bearing points.
I hope I've been clear here. Done this a ton of times with a tract co. I used to work for.
Write back if I've been foggy (or a fogey, which I can't help)
Cut the subfloor back so you have access to tops and bottoms of both the new and old joists. Place several big, heavy-duty bar clamps along the joists vertically, so that by clamping down on them you force the two joists to line up with each other. Nail the joists off together with a 12" alternating high/low pattern of 3" nails. Run a few 3"x5/16" lags or through-bolts through them for good measure. Now you can remove the clamps.
Now string-line the joist tops and plane off where it's too high.
If you can't do this because you haven't removed the finish floor in the kitchen and don't want to do so, then remove the old joist from underneath or at least cut the ends free so it's just so much dead-wood hanging in space. Since you won't be able to plane the high spots on the new joist, shim the low spots up to their level and set the whole joist that much lower. Notch the ends where they bear on the foundation wall or whatever if necessary. Asphalt shingles make good shims for this sort of thing, BTW.
It would have been a good idea to string-line the new joist before you installed it, though....
Dinosaur
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