joist not sitting flush to beam

67velle

I managed to move 2 2x6x12 under the beam. I put them about 1 foot off center either way. I had to trim about a 1/4" off the beams, but when I got them under the beam real good I then measured from the beam to floor and it measured 12' across the length of the beam. The outside walls are 12 feet too. It should be about as level as its going to get.

Now, I guess I need to install the other side, but go back and adjust all the joist hangers on the other side to get them flush with the bottom of the beam. What a bone headed thing that was.

The beam itself seems to slightly twist a 1/4". Probably due to me not having enough support under the beam and the PT wood being pretty wet when nailed together. When I nailed it together, lots of water came out on top of the nail.

Please keep your suggestions coming.

67velle

Here is a pic of the support beam.

Again, I cut about a 1/4" of a 2x6x12.

As you can see, the side the center beam is in full contact with, the center beam that measures exactly 12' to the floor.

Attached Thumbnails

 

woodworkbykirk

string a dry line across it really tight and use feeler blocks.. just because your measurement off hte floor changes doesnt always mean its sagging.. the floor might not be perfectly flat. the string will tell you more or use a laser level and measure the difference in the laser

67velle

Are you talking about stringing a line from the bottom of the beam across to the other side?

I dont really know what you mean by dry line and feeler blocks.

woodworkbykirk

take 3 peices of 2x scrap.. about 6" long.. nail one to the underside of the beam on each end.. now take a dryline (very strong nylon string) hook it on one end so it passes over the block and take it to the opposite end and hook it there doing so very tight.. now take the 3rd block and slide it under the string at the middle of the beam. if the block wont fit between the string and the beam, the beam is sagging.

this is something that is done for straightening walls before setting floor joists on top along with roof trusses

67velle

I gotcha.

67velle

How much sag is ok or not ok?

How would you go about correcting sag?

Should that be done before joist are put up?

67velle

Since it is obvious that the beam is twisted.

Does this mean the joist should be cut not square, but at a angle?

hand drive

there can be a little bit of space where the joists butts the beam( 1/4"), the hanger has a 1 1/2" bearing point so that allows a tiny bit of play but if more than 3/8 of an inch twist then cut the joists to follow the twisted beam.

I'm not sure how far along you are in the process but I always install the joists to the beam with toe nails and add hangers later, it makes the job much more complete and you can line the underside of the joist flush to the beam every time and you can see where the joist butts to the beam...



Also, if you are having deflection problems with your beam before the thing is even fully built then I'm not sure what could possibly help that beam at this point other than a stronger one.

67velle

Im right at the 1/4" on several joist. Thats good to know.

Well, I have one side of the beam completely installed, but have been thinking about taking many down and redoing them.

I was thinking that. I tried that, but being a inexperience carpenter, I could not hold the joist with one hand and hammer with one.

Well, I do not think the beam is all that bad, but yes, I dont think anything can be done about it. Its kind of clear to me that the beam went up while the wood was still wet and then I did not get the joist installed the same day, several days later, due to my work schedule, the joist got put in. Did not noticed that the beam had slightly twisted till it was to late.

carpdad

There is no good sagging, for house or for us.
The center girder, what is the span? Triple 2x6 is way inadequate, especially as yours was pieced together. Even with overlapping the joints, that is actually two 2x6 solid wood with a hinge in the middle. Where outside 2x's meet, you actually have one 2x6 in middle trying to hold the weight. You should have support posts where these hinges are.
If it was as easy as putting a support under the mid span to straighten the girder, ,,,you see what I mean. You can try sistering 2x12s and bolt the whole thing together, but even 2x12 has limits on how much it can span. You may have assembled the girder with crown down, but anyway, 2x6 does not give enough width for the nails that you need to assemble a girder.
The sagging may look acceptable now, but as time goes on, it will get worse, cracking the sheetrock, pulling in the walls that the girder is attached to, and possibly the load points failing.
What to do from this point on is your decision. Personally, I would take it as a lesson and remove the whole thing. This is where your cars, properties and family will be. Take new photo of entire garage, draw a clean simple plan, and attach with what/how you want to use the garage for. In a hurricane zone, you really need engineer's advice, or at least from a builder who is well informed with personal inspection of that garage. Shear walls, ties and cables can make the structure tighter, all from inside.
It is really just my opinion based on the photos. I may be wrong, but the sagging girder is not a simple fix. It is good that you haven't added more to it yet. One thing, though, the girder ends, where opposite ends are sitting on the wall plate, you must add more studs that go to foundation. Make sure you see the continuation to the concrete. But again, really think about removing the whole thing and start over. 5 years from now, the money and time lost will be nothing compare to failing structure you will be looking at.

hand drive

I know what you mean, some houses I've built it seemed like having 6 arms would not be enough . For beams and long easy joist runs I set up a walkboard across the span under where the beam is that puts me while standing on the walkboard about eye level to the beam and if setting the joists myself while facing the beam and standing on the walkboard I use my shoulder to hold up the joist while nailing it to the beam with my two free hands. as you are nailing just keep the joist pressed tightly to the beam so it does not bounce around. sometimes a toe nail down through the top of the joist into the beam is the easiest to get started with then just tap the joist with a hammer to get it fine tuned to the underside of the beam and on layout and finish nailing it.

67velle

The length of that beam is a little over 19 feet.

It sounds like by using the word grider. You are advocating installing a steel beam instead of wood.

Could I just take down that wood beam and replace it with a steel one and then attach the joist to the steel beam?

It sounds like a 20 foot steel grider, like a I beam sitting on top of its on support post right up next to the walls is what your advocating. That way the steel beam is entirely on its on supports.

67velle

Interesting.

So, do you have a opinion like the above guy about taking all that down? I have a hard time swallowing the fact that the plan of a 10 year carpenter is wrong....

hand drive

19 feet and 2x6 do not match in any way possible, and you cannot really effectively make the beam wider to compensate for the lack of height in the beam. For 19' the beam should have been at least built from 2x12 lumber.

There are a couple of options. Since you have it somewhat built why not add another beam (dropped beam) under your beam with multiple 2x4s under the beam where it lands at the walls. head height might be an issue with the dropped beam though. The other option is to start over with a heavier beam, you might could add a temp wall support for your joists and take the beam apart and add the new beam in building it piece by piece.