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Old 05-02-2013, 09:00 PM   #16
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garage ceiling joist end cut


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Surfaced 4 Sides
I understand the term, just not why he would use the s4s.

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Old 05-03-2013, 12:03 PM   #17
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garage ceiling joist end cut


There is not enough wood to effectively support a 2x8 by its self. You will likely have to build your own truss system in place or support the 2x8 properly with an angled brace or gusset to support that area. The angle I indicated in the picture shows how that would be placed.

As far as the span goes...to far without a truss system.


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Old 05-03-2013, 12:09 PM   #18
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garage ceiling joist end cut


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Originally Posted by one cut View Post
I understand the term, just not why he would use the s4s.
Hey, this guy buys the best.
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Old 05-03-2013, 01:57 PM   #19
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garage ceiling joist end cut


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Originally Posted by MJ Force View Post
There is not enough wood to effectively support a 2x8 by its self


Attachment 70268
At 3" deep, there is sufficient timber in the cross-section to adequately take the shear stress at the bearing without adding a gusset plate (assuming normal domestic ceiling loading).
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Old 05-03-2013, 02:57 PM   #20
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garage ceiling joist end cut


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Originally Posted by tony.g View Post
At 3" deep, there is sufficient timber in the cross-section to adequately take the shear stress at the bearing without adding a gusset plate (assuming normal domestic ceiling loading).
You COULD saw a notch out of the top plate to gain another 1-1/2". I'm not sure, but I think your bearing height is figured for an angle of repose of about 45 degrees... that might help.

But then.......... how would you get the joist up into that notch? Hummm. Maybe not a workable suggestion.
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Old 05-03-2013, 11:54 PM   #21
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You could use a hanger under the bottom if notching more than acceptable (though it appears you may be good); Fig.4. The taper-cut has a maximum, Fig.7; http://www.google.com/url?sa=t&rct=j...,d.cGE&cad=rja

Remember the height/slope measurement is at the back of the 1-1/2" minimum bearing, not the very back of the joist.

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Old 05-04-2013, 07:17 AM   #22
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garage ceiling joist end cut


Quote:
Originally Posted by tony.g

At 3" deep, there is sufficient timber in the cross-section to adequately take the shear stress at the bearing without adding a gusset plate (assuming normal domestic ceiling loading).
According to the site posted by "Gary in WA",

Quote;
"[B]Tapering Joists and Beams[B]
It is sometimes necessary to taper the ends of a beam or joist to keep it under the slope of the roof. But reducing the depth of these members also reduces their load bear- ing capacity.
If joists must be tapered, make certain the length of the taper cut does not exceed three times the depth of the member and the end of the joist or beam is at least 1/2 the member's original size."
End quote.

So, if the load bearing point (as shown in my diagram) of the joist where it meets the plate is 3", this joist cannot be effectively used without proper trussing or bracing. Especially not over a 19' span.

If a taper cut is used for a 2x8, the point at which the joist meets the top plate must be minimum 3 3/4". The length of the tapper cut appears to be within the minimum (3 x the dimensions or 22 1/2". The criteria of both rules must be met. It appears to me that only one is.
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Old 05-04-2013, 01:08 PM   #23
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MJ;

Codes are generally written as easy-to-follow rules of thumb so that architects, contractors, framers, self-builders and inspectors can work to an accepted standard without the need for further structural appraisal or calculations.

But, consider the OP's case;

On a span of 19ft @16" centres, and assuming a dead load of 10 psf with no storage, the total load on each joist will be about 260 lbs. This means the shear force at the bearing will be 130 lbs, and the shear stress on the reduced section of 1.5" x 3" will be 43 psi. The allowable shear for a timber such as Douglas Fir is around 100 psi. Even this figure can be increased by 10% because the ceiling joists form a load-sharing system. There willl also be a further increased allowance because the cut-out is at the top of the joist, rather than the underside. Without working it out fully, my guess is that the reduced section will be taking considerably less than one-half the allowable shear stress.

The point I am making is that to go outside a code does not imply inadequacy; it merely means that an inspector may ask for justification. In the OPs case, the cost of structural calcs would probably not be worth it.
As one poster suggested, it might be better to cut notches from the wallplate to maintain a greater depth of joist at the taper, and stay within code.
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Old 05-04-2013, 04:07 PM   #24
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As these appear to be ceiling joists, which require X number of fasteners into the rafter (heel/joint connections, bottom chart; http://publicecodes.cyberregs.com/ic...9_8_par027.htm) to prevent wall spreading, I would suggest a different approach; add a 2x4 ledger board to the top plates, notch the joists to fit, you will have code-approved bearing of 1-1/2" and meet the "tapered top" rule. Use a drill hole at the notch apex to retain strength/prevent splitting; pp.3; http://www.finehomebuilding.com/PDF/Free/021184090.pdf

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Old 05-04-2013, 04:23 PM   #25
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Of course, this COULD be done the simple way... if you can stand to lose some head room....

Just install regular hangers, 7-1/2" down from the underside of the roof (or deeper if you choose to go with 2 x 10's), and put squared-off joists right in the hangers.
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Old 05-04-2013, 04:35 PM   #26
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Quote:
Originally Posted by Willie T View Post
Of course, this COULD be done the simple way... if you can stand to lose some head room....

Just install regular hangers, 7-1/2" down from the underside of the roof (or deeper if you choose to go with 2 x 10's), and put squared-off joists right in the hangers.
But how would he tie the rafter feet together to stop roof spread?
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Old 05-04-2013, 04:42 PM   #27
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Originally Posted by tony.g View Post
But how would he tie the rafter feet together to stop roof spread?
What's been taking care of that for the many years this garage has already been standing there?

Besides, the joists will be nailed from the sides, through the hanger holes... at both ends.

Worse comes to worst... leave the bottom few inches of each end of the joists 5-1/4" longer (or whatever the stud width), and nail that part into the studs...... You would, of course, have to use the long, "wrap-around" hangers with open backs, and slip them on after installation.

Yes, I know this would require some backers for hanger nailing..... So add some bridging there. And, yes you will have to rearrange the stud-to-plate clips. (Ya gotta have SOMETHING to do.) If THAT'S too much..... move away from the studs, and just nail upward, through the little joist extension, into the bottom of the plate.
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Old 05-05-2013, 10:20 AM   #28
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garage ceiling joist end cut


Quote:
Originally Posted by tony.g
MJ;

Codes are generally written as easy-to-follow rules of thumb so that architects, contractors, framers, self-builders and inspectors can work to an accepted standard without the need for further structural appraisal or calculations.
All due respect. As architects, engineers and builders we interpret the codes, regulations and rules as they apply to our unique situations. Every aspect of construction would be difficult to write as an easy-to-follow, unless your Ikea. And even those simplified instructions can be misinterpreted.

100 carpenters could build the same house 99 different ways.
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Old 05-05-2013, 11:04 AM   #29
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Originally Posted by MJ Force View Post
All due respect. As architects, engineers and builders we interpret the codes, regulations and rules as they apply to our unique situations. Every aspect of construction would be difficult to write as an easy-to-follow, unless your Ikea. And even those simplified instructions can be misinterpreted.

100 carpenters could build the same house 99 different ways.
I do not disagree with the gist of what you are saying, but my thesis is that if a detail does not follow the code, it does not necessarily mean it is inadequate.

As a code is likely to be used by people whose skill varies from experienced framer to ham-fisted DIYer, it has to be (1) simple to follow and (2) set standards greater than the minimum, to allow for poor materials or workmanship.

The OPs case is a very simple one, and if the timber stresses are within the limits I don't believe any engineer would see a structural problem. The problem lies in the cost of producing calculations to prove it! This is why in most cases it is easier just to follow the code.

But what a dull world it would be if we all had to build to a rigidly prescriptive code, with no flexibility allowed!


(by the way, getting a doctorate in finite element analysis is easier than following IKEA instuctions).

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Old 05-05-2013, 02:15 PM   #30
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A big problem for builders, (DIY to GC), is the lack of imagination, vision, or sometimes even "knowledge" on the part of inspectors. They arrive at a job site armed with an old, weather-beaten drawing that shows them how someone, somewhere envisioned a particular phase of construction, and "By God, this is how it's done... and no other way."

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