Straightening twisted floor joists?

[GreenRaven]

We live in a small cheap 3 bedroom ranch built in 1976. We are the 2nd owners, it's our first house. We've recently noticed, while doing some work in the basement, that about 2/3rds of the floor joists in the basement are twisting on the main beam. They are no longer perpendicular on the beam but are on an angle. / , not | , when viewed on end. Some are worse than others.

There are a few slightly saggy spots in the floor upstairs and it's starting to squeak.

A few more details:

1) The joists are 2 x 10s, 16" on center. 2) The span is 12 - 13 feet - because of a stepback in the front of the house one end is 24' across, the other is 26'. 3) Metal X bracing is installed at mid-span for most joists, but is missing where ductwork is and in a few other places. 4) The joists do not overlap each on the main beam, they are butted against each other and a single plywood gusset of about 1/2" thick, 6" wide, and 2 feet long --stapled-- to the joists across the joint. 5) No toenailing is apparent where the bottom of the joist meets the beam. 6) No blocking was installed where the joists meet the main beam.

My questions:

1) Is it possible to straighten the twisted joists? If so, how? 2) Should the joists be sistered with more 2 x 10 across the main beam or put in more plywood gusset before putting in blocking? 3) Can you block or sister with that small plywood gusset in place or should it be removed to get full access to the sides of the joists? 4) Will jacking anything up be required? What gets jacked? It seems like a bad idea to jack the joists that are at an angle as you may roll them over more.

The more information you can give me, the better, as we decide what to do (and who will do it - we do a lot ourselves but this may be contractor territory).

We would like to punch both the builder and our building inspector right about now. Both were idiots - the builder butchered a lot of stuff and the inspector never caught it, and we were too green to know what we were looking at.

Thanks very much, Liz

[Duane Bozarth]

Possibly possible, but of no real consequence.

Are they failing?

I wouldn't mess w/ it at all unless there's some real problem (like a serious sag and you don't mention anything except a little squeaky flooring...)

See above...

Find the places where the floor has some give and squeaks and insert shims between the top of the joists w/ construction adhesive and drive them in firmly. Will solve the problems in all likelihood.

What's the flooring above? Depending on what it is you may have some other recourses that can be taken in addition, but the above should take care of the problem.

Unless there is a _major_ sag, doesn't sound like anything at all serious to me.

Wood moves and it is not at all uncommon for joists to twist some. After 20 years, they've done what they're going to do.

[GreenRaven]

What do you mean by "is the joist failing"? What's the criteria for this? To me it seems they are since they're sliding sideways on the beam, but I don't know what failure criteria commonly is. They're not cracked or rotted, just on an angle.

We are looking at selling in a year or two and don't want this to be a showstopper for the sale. I'd think twice about buying a place where the joists looked like this.

We're also getting some small drywall cracks near the molding and ceiling over the worst-rolled joist, which is under the hall closet.

And if we stay there's nothing to stop them from sliding further, since there's no blocking or toenailing to stop them.

The subfloor is 3/4" plywood and is in fairly good shape. It's all carpet or vinyl flooring so we have no problems with cracking tile or hardwood.

Liz

[BP]

It can be done but don't expect perfection. You should have solid 2x10 blocking over the beam and between the joists anyway. In Mass this is required by code now for fireblocking. You cut 2x10 blocks 14.5" long and get them in place on an angle and then beat the hell out of them to drive them in parallel with the beam and blocking both the front and the back joists. You may need to cut them shorter on the badly twisted joists. If they wont drive in they wont drive in. Cut em. You can use an 8 foot 2x8 or

2x 10 to use as a lever to twist the joist back close to straight, or pipe clamps or come-alongs or anything. This is a two person job and not for the dainty. By the time you are done you should be exhausted and have absolutely no aggression left in you!

No. Unless you see physical evidence of a break or a large crown or dip (>1/2"+). "Checking" (long cracks going with the grain) is normal and not usually a structural issue. 2x10 can easily span 14' on a first floor.

No need to remove it. Drive some more nails in it.

Can't comment on that sight unseen. You need to have a pro look at the whole structure.

The most likely cause of the squeaking floor is the metal bridging. It is notorious for this. I have done several replacement jobs in my area to solve this problem. Cut out all of the metal bridging and replace it with wood strapping for bridging. You can leave part of the metal that goes under the plywood in place and just bang it down flush with the joist. After that run a bead of construction adhesive down the joint between the joist and the plywood on each side wherever you can reach. Press it into the joint with your finger. Stay off the floor for at least 8 hours.

Everything you explained was "state of the art" for the 1970's. They don't build em like they used to, and that's a good thing.

[GreenRaven]

Thanks. More questions (sorry I'm such a pain):

- Would it be helpful to move everything out of the room above it before we start banging away, to reduce the weight on the joists from above?

- Is any jacking needed to get the weight off the joist before banging on it or will the banging be enough?

- Does the blocking have to be right over the central beam or can it be off to the side a little? I ask this because of the stupid plywood gusset. Because it doesn't cover the full width of the joist I don't think I could get smooth fit - there will always be a gap between the blocking and the joist at the un-gusset areas above and below the plywood.

Here it is viewed from the side:

______________________________________ joist 1 | joist 2 ___________________ | | | gusset | ---------------------------------- |

---------------------------------------------------------

- And since there is no joist overlap at the beam should I be running a line of alternating blocking down either side of the beam, since the joists aren't really joined well and when I block one joist it won't

100% stabilize the other side?

Aggression and exhaustion won't be a problem, I'll just pretend it's the building inspector :lol: . .

That's a terrifying thought.

You got that right.

Liz

[Goedjn]

Yes, you can straighten the joists, but doing so may wall produce nailpops and cracking wallboard above, because the plywood subfloor is going to heave a little bit.

You build a big-ass wrench out of dimension lumber, bolts, and plywood, sort of like a peavy with a fixed tooth, and pry the joist vertical, and have someone stuff blocking in there while you hold it.

Where there's something in the way so you can't put in blocking, bridge across the bottom of the joists with a 2x4 until you cross two joists that ARE blocked, on each side.

(see

for the sketch of the prying tool).

After doing the whole floor, inspect the topside for things that have popped up.

[BP]

Helpful? Maybe. Necessary? No. Unless you've got a 400 pound TV or something....

No. But if you've got the time and the gumption then go for it. It will be less Neanderthal than muscling the blocks in. You need two jacks and a crossbeam about 36" long made up of 3 2x6 nailed together. Place the crossbeam across 3 joists with the target joist in the center about 24" away from the beam and using a small test block of 2x10 jack s-l-o-w-l-y until the test block slides in nice and easy. Do both sides and then install the fireblock.

Three options:

1- remove the gussets and throw them away. As long as the joists bear at least 2" on the beam and are toe nailed into the beam they are unnecessary anyway. 2- remove the gussets and install new gussets that are 9.25" tall. 3- cut strips of plywood to infill the top and bottom of the gussets to fill in all 9.25".

The fireblock is 1.5" thick. it should cover 3/4" of both joists on both sides. One in every joist bay. Or you could double up the fireblocks, 2 in each joist bay. It's common sense. You want to block both joists, both sides, any way you see fit.

He wouldn't care. Believe me!

You should see what they could get away with in the 1950's!!

[anoldfart2]

Just punch those guys and you will feel much better. They deserve it and we all know you really want to do it.... :) Heck, the sound waves generated by the punch might even twist them boards back where they belong.

[Harry K]

I can see straightening one that is free but how do you do it in this situation? The subfloor at least if not also the finish floor is nailed into the tops of those joists. Any straightening has to bend and pull on those nails.

Harry K

[BP]

Not really an issue. If the joists were well nailed they wouldn't have twisted so badly in the first place.

>

[Harry K]

Good point!

Harry K

[Duane Bozarth]

I'll bet when OP tries this he/she will find there's a whole lot more resistance there than they're expecting...

[BP]

And you would win that bet.

[Duane Bozarth]

:)

Haven't seen it, obviously, but I'm still of the opinion there's probably not much, if anything, seriously wrong structurally and they're fussing mostly over cosmetic issues. If there were truly serious structural faults, they'd have shown up in the 20 years as more than a few squeaks and small settling cracks.

[GreenRaven]

Yeah, I'm expecting to not be pretty. After all, it's had years to get like this, and undoing it in an afternoon won't be possible.

But at the very minimum we need to stop it from getting any worse. We have to at least try.

There doesn't appear to be any toenailing on the joists themselves, just that plywood gusset. And the subfloor is glued (can see the drips) and screwed (can see screws hanging down where they missed the joist from above).

I'm expecting some possible mess upstairs with stuff popping up or maybe cracking, but since we need to recarpet and repaint the whole house interior this is a good time to do it.

No 400 lb TVs, but we do have a bunch of books.

Liz

[Duane Bozarth]

I really don't believe it will get significantly worse unless there is an actual fault which it doesn't sound like there is . If there's only some minor settling and a squeaky floor here and there after 20+ years, it's pretty good indication of no _major_ issue.

Not being able to actually see what you're talking about, I'd probably add the fire blocking if there are places that really need it/it will make a difference if you do (but if it's an open, unfinished basement as it sounds like, there's nothing for the blocking to block against, so even that doesn't seem certain to be a real issue.) If there are a few joists which have really moved significantly (like an inch or more), I'd consider those few, perhaps as worthy of some attention. If I understand the way you're describing it, adding a hanger bracket might be the easiest way to ensure they don't go anywhere further than they've already gone.

[GreenRaven]

There are about 3 joists where movement is more than an inch. On the worst one, the sliding has pulled the gusset right off the joint (the opposite side joist is still straight). The worst areas are around the duct work spaces where no X bracing or anything was ever installed.

It's also worse on the side that correlates with the front half of the house. Might be that there has always been more furniture on that side, or that the snow weight has been heavier as it's the north side of the house and the south side of the roof rarely gets snow buildup because the sun melts it, I don't know.

Of the rest, about 1/3rd have movement from between 1/2 to an inch, 1/3 are a 1/2 inch or less, and the last 3rd are pretty much straight.

I'm mostly worried about the 3 bad ones, and about keeping the others from getting that bad.

Liz

[Duane Bozarth]

About all I'd do I suspect then would be to repair the worst and add bracing where it is lacking. Blocking cut to fit reasonably tightly between the remainder will provide no place for them to go and can be done much more simply than trying to return them to the "full upright and uncomfortable position"... :)

[Goedjn]

It's not caused by weight, it's caused by using bad lumber for the floor joists, and not installing it properly.

[Duane Bozarth]

Well, it could be exacerbated by settling or perhaps the house has shifted in one direction or the other although that would tend to produce a uniform relative movement and they would all be tilted the same way.