What tie should I use to attach joists to a beam sitting on top of the joist. I know I could put it in flush with the joist and just use a regular joist hanger , but I would like to put the beam on top. The joists are 2x6s and the beam is a 4*12.
This is an unusual situation--I doubt there is a piece of hardware made specifically for this. Simpson strong tie sells heavy duty twisted straps that would work, though i don't think they are made for that purpose (google it). If you are dealing with a building inspector, they might want to see it engineered.
A 'hurricane' strap would do it (the ones for connecting rafters to top-plates), but you could probably just toenail it. This sounds unusual, why are you putting a beam *on top* of joists?
A beam indicates it will be carrying a load so the joists would have to be supported to carry the beam. A 2x6 joist can't even span 10' @
16"OC, nevermind carrying a beam and additional load.
load.http://www.awc.org/calculators/span/calc/timbercalcstyle.asp>
I think he wants to hang the joists from the beam- Ed, please clarify.
Dave
load.http://www.awc.org/calculators/span/calc/timbercalcstyle.asp>
That was my take on it too. Using normal terminology, beams support joists, not the other way around.
I imagine what the OP is doing is removing a load bearing wall and does not want to put the beam in the room, but in the attic instead, above the rafters/joists. I have seen it done before, but never paid attention to how it was attatched. First, I would go to the Simpson section at HD/Lowes and check them out. They have fasteners for nearly every imagineable use-- may find something that would work. If not, you could get metal "L" shaped plates with a hole n both parts of them and bolt one to the joist and one to the beam such that holes in each line up and hook them together with all thread and nuts. Larry
Any local welder can fabricate brackets to your specs if you can't find something on the shelf.
Another thing came to mind-- if you look at the Simpson Strongtie stuff at the box store, see if they have a catalog there where all that stuff is located.(They do here) Just because HD/Lowes does not have something doesn't mean that it does not exist-- just may take some extra time and effort to get it or special order it. Also see if Simpson has any info on the web. Larry
I don't want to just hang the beam, I want it on top (because I am removing a wall below and don't want it to show). The beam will be supported with blocking at both ends, so the beam will still support the joists. I looked through the simpson site and didn't see anything that jumped out at me for this.
If I have to, I will inset it and use hangers, but that will be more work and the 2x6s are old so they are wider then 1.5 inches, so might not fit a regular hanger. As for the joist size, the joists are already there and they are just in the attic over a relitivly short span, so that shouldn't be a problem
Getting a cutoms welded bracket is probably out of my price range.
Thanks
There is pre-drilled angle iron "sticks" 4 to 6 feet long in the big box stores. Just cut to the length you need and bolt in place.
Tom J
Typically the 2x6 ceiling joists would be sitting on the wall top plates, so it should be a simple matter to sit the 4x12 beam on the wall top plates so the bottom of the beam is aligned with the bottom of the ceiling joists. If the issue is that you don't want the beam to project horizontally the additional 3.5", just cut back the ceiling joists 3.5" so the beam doesn't project. Be sure that the built-up posts in the walls supporting the beam are adequate.
No problem, joist hangers are made in a variety of widths, including sizes for rough lumber.
Cheers, Wayne
Now I get it.
Maybe something along the lines of these things
Go to a real lumber yard like 84 Lumber and ask them. There has to be some kind of ready made hanger to do what you want.
That's the reason I suggested the pre-drilled angle iron for this application.
Tom J
The beam will not support anything that is below it. it must be placed underneath the load for any support to occur. Is this you own personal fantasy or did you run this idea past anyone with any experience like a carpenter?? It sound like you thing these hangars are going to support the load. That is wrong headed in my opinion.
You will need a damn strong bracket if you are doing what I think. You likely wont' find it on the shelf. If you design the bracket and provide drawings you can hire a welder/fabricator cheaper than you might think. Where I live metalworkers are everwhere and every farmer and mechanic does welding. Everything is negotiable with these guys and a lot are out of work.
I always want things like this to be many times stronger than actually needed, but this is not going to require some 1/2" thick steel brackets. Look at the weight a joist hanger will support vs. how light and flimsy they look. Larry
Did you tell that to the beam? If the beam has to be below the load, how do you explain joist hangers? Ever see a suspension bridge or floating walkway?
Like a joist hanger?
If you design the bracket and
A joist hanger works with gravity supporting the load from underneath with multiple nails. Other larger nails also hold the joist in place. If you want to support the beam it from above then it must be supported from above perhaps with steel cables and turnbuckles. It would be more than unusual.
Roof joists or collar ties are not usually large boards but they are vital to the structural integrity and must be supported from underneath and they should not be attached to the beam in the way suggested. Rather, steel cable could be attached to the ridge beam which could be beefed up would be a more likeley solution in this unusual scenario.
No, it is not impossible but a more conventional approach can most likely be used. If the OP insist one this wacky idea I suggest he hire an experienced carpenter or engineer to OK the framing design.
and made to look nice with some moulding. That is a more conventional solution and easier to design and execute.
Say what? Gravity is supporting the load? You claimed a beam had to be underneath a load to support it. That, obviously isn't true. The most widely used joist hangers obviously support a load that is attached to the side of the beam.
Other larger nails also hold the joist in
Go back and read the question. He doesn't want to support the beam from above. He wants the beam to support the joists that will be below it. Unusual yes, but certainly possible with the correct metal brackets and without cables and turnbuckles.
If a beam can support the weight required by the joists, and a bracket is used to connect them, then it can support the structure whether from above or below. The obvious and very std joist hangers already attach to the beam from the side, shooting your whole argument down. And if that ain;t enough, here's a link to a supplier that has something pretty close to what he's looking for:
Like turnbuckles and cables, instead of simple metal brackets? LOL
the OP insist one this wacky idea I suggest he
practical standpoint I think the beam could be inside the room
The beam doesn't care whether the load it's supporting is above it, below it, or tacked to the side. The only issue is making sure that the hangars are capable of supporting the load on the joists.
Since these are 2x6s, one assumes that the span tributary to the beam isn't more than 10'. If the joists are 16" o.c., that's 13.33 (call it 14) square feet. Since OP is willing to have the beam above the joists, one assumes that it's not a load bearing floor, so we can call it pessimistically
30 PSF, or 420 pounds per hanger.I don't think there's any commonly available steel with a yield strength of less than about 20,000 psi, but lets use 10,000.
The easiest way to support the joist is to wrap the strap around the bottom of it, run it up both side, up one face of the beam, so there's one strap up each side of the joist, and hook both ends over the top of the beam. Each half needs to support 210 pounds. On the other hand we're bending, twisting, and drilling holes in it, so we'll triple that value, and call it 630 pounds. Since our cheap-ass recycled steel bar-stock supports 10,000 psi, that means we need a strap with a cross section of .063 square inches.
Half-inch strap iron 1/8th inch thick is, conveniently
0.0625 square inches in cross section.Hmm... common box nails, in sheer, 3" penetration ... call it 100 pounds per nail. which works out to 6 nails per strap.. That seems excessive to me, but hell, the point is to make stupid overbuilt...
So put 3 nails slanted one way, 2 the other, up the face of the beam, and a sixth on on top.
Attach the brackets to alternating side of the beam on each successive joist, so it won't be tempted to roll. Put blocking between the joists near the beam so that even if some nut-case screws a swing into one of the joists, it can't pull sideways and behead the nails one at a time.
Remember: Goedjn is not an engineer. Goedjn is an anonymous voice on the internet. Do your own math.
--Goedjn
I don't really understand your project, but welding is a lot cheaper than I imagine it. The guy around here is in a suburban, neighborhood welding shop. I don't know what the bulk of his work is, but the last pair of things he welded together for me cost about 10 dollars. Another guy on the opposite side of town was going to charge about the same, but I didn't have the parts with me. In my case, the two parts belonged to me. I suppose he'll charge a bit to provide the steel.
It's good for you to look into this. Maybe you are like me. I always imagine that something I have never bought before, and that my parents had never bought, is very expensive. Lucite, foam rubber, welding were all much cheaper than I imagined. The 6 x 12 piece of lucite I wanted was a dollar! I thought it would be much more.
Of course in this case, I don't know how complicated the bracket is, and I could be wrong. :) but check.
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