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Rafter thrust control for flush beam

If the beam calcs, it seems they could "purlin" that ridge, maybe double 2 x 6 up to it every 4 feet. Straps are going to give the drywallers fits, and probably require some sistering of 2x4's on the joists for fastening purposes.

Brent.
 
jwilly3879 said:
They can put the straps on top of the joists
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Beam is probably larger than the joist, you just can't see it from the camera angle. doubt seriously you can strap on top.

Great minds and all... :)

Brent.
 
Straps can be placed on the "bottom" of the joist, though is creates issues with gyp bd nailing

Or add ties

hb077QA01-04_lg.jpg


There are always options....
 
I have no idea why the beam is there because they could have replaced all of the ceiling joists to make that span but they gutted this house and wanted an open floor plan. I believe the used the beam as flush to replace the wall that was there being used as the splice point for the ceiling joists. The CJ and the ridge have zero relevance to each other since the ridge is a board as you can see and not a ridge beam at which point my photo and post would not be relevant.

I have required strapping to ensure rafter thrust control. The drywaller can bitch all he wants.
 
MASSDRIVER said:
Beam is probably larger than the joist, you just can't see it from the camera angle. doubt seriously you can strap on top.Great minds and all... :)

Brent.
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You are correct oh wise one Brent. They must strap the bottom to please the drywall guy.. ;)
 
jar546 said:
You are correct oh wise one Brent. They must strap the bottom to please the drywall guy.. ;)
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Hey don't get me wrong. Never pass up an opportunity to screw with the drywaller. Fun is fun. But you have to give him a CHANCE at least.

If you strap it (depending on length) you are creating an area he simply cannot fasten to, unless you sister on some nailing, or let him drill into straps. Or tension ties.

Brent.

Looks like they tried what we did here. Our ridge is directly over the beam and supported by it.

 
Last edited by a moderator:
I have required strapping to ensure rafter thrust control.
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Just curious.

How long do the straps have to be?

What are the fasteners required for the straps?

What is the loading used to determine the above questions?
 
4thorns said:
Just curious. How long do the straps have to be?

What are the fasteners required for the straps?

What is the loading used to determine the above questions?
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There are many calculators available for this and equations available to anyone. Once we know the span, spacing, pitch, snow and dead load the thrust can be determined. Simpson has specifications on appropriate strapping for this instance. There are some that have determined the strapping equivalent to the ceiling joist connection nailing requirement too. It is much easier than people think thanks to engineered products. That saves us from sending a framer to an engineer all the time.
 
jar546 said:
There are many calculators available for this and equations available to anyone. Once we know the span, spacing, pitch, snow and dead load the thrust can be determined. Simpson has specifications on appropriate strapping for this instance. There are some that have determined the strapping equivalent to the ceiling joist connection nailing requirement too. It is much easier than people think thanks to engineered products. That saves us from sending a framer to an engineer all the time.
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Jeff,

Which Simpson strap is called out?
 
Rider Rick said:
Jeff,Which Simpson strap is called out?
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Using nails, an LSTA18 works best unless the holes line up with the LSTA12 since it has to span the beam width and joist hangar bottoms. Anything from the LSTA12 on up works with nails. With simpson screws the numbers are even better
 
There are many calculators available for this and equations available to anyone. Once we know the span, spacing, pitch, snow and dead load the thrust can be determined.
Click to expand...
Who is responsible for determining this information and the required connection? Is this something you would determine and inform the builder?
 
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