Tie to attach joist to beam above it

Posted by Lawrence on February 9, 2007, 8:58 pm

On Feb 9, 2:17 pm, LP1...@webtv.net (lp13-30) wrote:

> 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

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.

>From a practical standpoint I think the beam could be inside the room

and made to look nice with some moulding. That is a more conventional
solution and easier to design and execute.

Posted by on February 9, 2007, 10:02 pm

> On Feb 9, 2:17 pm, LP1...@webtv.net (lp13-30) wrote:

> > 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

> A joist hanger works with gravity supporting the load from underneath
> with multiple nails.

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

> 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.

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.

> 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.

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:

http://www.expamet.co.uk/bp/products/batspee3.html

Notice the part about "underslinging joists"?

> No, it is not impossible but a more conventional approach can most
> likely be used.

Like turnbuckles and cables, instead of simple metal brackets? LOL

the OP insist one this wacky idea I suggest he

> hire an experienced carpenter or engineer to OK the framing design.>From a

practical standpoint I think the beam could be inside the room

> and made to look nice with some moulding. That is a more conventional
> solution and easier to design and execute.

Posted by Goedjn on February 10, 2007, 12:02 am

wrote:

>On Feb 9, 2:17 pm, LP1...@webtv.net (lp13-30) wrote:

>> 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

>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.

>>From a practical standpoint I think the beam could be inside the room

>and made to look nice with some moulding. That is a more conventional
>solution and easier to design and execute.

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

Posted by on February 9, 2007, 3:58 pm

> > 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.

> 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.

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?

> > 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.

> You will need a damn strong bracket if you are doing what I think. You
> likely wont' find it on the shelf.

Like a joist hanger?

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.

Posted by DanG on February 10, 2007, 8:15 am

I'm sorry, Lawrence, you just aren't right. This has been done
for ages to remove bearing walls. It is important that the
carrier beam be sized for the load and that the holding method be
adequate. Why would the beam care if the joists were on top, in
plane, or underneath? It is still a uniformly distributed load.
It would be much lighter for the OP to make a truss. Take the
precut pieces up in the attic and assemble in location. My age is
showing now, but I have seen the hangers done with 2x2 lumber and
nails. I would definitely go with the angle iron approach.
Prepunched is fine, but expensive. A joint of 2x2x1/8 would be
less expensive and you drill your own holes, though the Simpson
twist straps might be adequate. Engineering input is always
preferred.

--
~~~~~~~~~~~~~~~~~~~~
DanG
A live Singing Valentine quartet,
a sophisticated and elegant way to say I LOVE YOU!
valentine@okchorale.org (local)
http://www.singingvalentines.com/ (national)

>> 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.

> 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.

>> 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.

> 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.
>

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Tie to attach joist to beam above it - Page 4