Roof Beam replacement.

[hosspuller]

Gotcha. very helpful.

So the come along would essentially be a temporary stabilizer to keep the walls from bulging while working on the truss.

Yes ... As others have posted, That cracked piece isn't a really a load bearing member, it's in tension. Notice the vertical crack, If it were a loaded beam, the crack would be on the bottom. I surmise only the broken piece is fastened to the vertical post. The unbroken section is free to move. Even with the supports pictured, if you cut it, the roof may collapse, not merely bulging the walls outwards
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[Streetcar]

The easiest and probably best repair is add a couple of pieces of steel angle iron to the bottom of the cracked member. use structural screws to attach angle to beam. The connection points of the truss are designed and would need to rebuilt in similar strength

 

[zzvyb6]

Why not just lash another beam along side ? Be done with it. If the wall has pushed out. Pull it in. The building seems shy of enough vertical roof support. Maybe even another truss on each side, appropriately spaced.

 

[Chewwy]

Why not just lash another beam along side ? Be done with it. If the wall has pushed out. Pull it in. The building seems shy of enough vertical roof support. Maybe even another truss on each side, appropriately spaced.

Good idea, although based on the picture in post no. 8, the entire building appears to be lacking in verticle support at the walls as well as spacing between the end and center truss. Unlikely this building meets the building code.

 

[hosspuller]

The easiest and probably best repair is add a couple of pieces of steel angle iron to the bottom of the cracked member. use structural screws to attach angle to beam. The connection points of the truss are designed and would need to rebuilt in similar strength

This is a "depends" solution. If the bottom of the cracked member is not fastened to the roof member or inadequately connected, then the wall will push out collapsing the roof.

To my eye, the "beam" has failed in tension. The upper portion has sheared horizontally with the "vertical crack" a tension failure

I think the temporary shoring is taking enough load off the truss to prevent roof collapse. But the shoring doesn't fix the broken truss connection.

 

[MAX-24-Dean]

If the wall has pushed out. Pull it in. The building seems shy of enough vertical roof support. Maybe even another truss on each side, appropriately spaced.

I believe this observation to be correct, not enough vertical posts and not enough trusses to keep this building living in a snow zone.
I would recommend having a good carpenter take a look for structural loading for the snow load and wind loading for your area. They will tell you right away if the spans of the perlins are to long or if there are not enough trusses.
The only thing I would do at this point is to take a come-along and place tension from one post to the opposite post until you get a qualified carpenter out looking at it. just snug it up not moving anything.

 

[BlueKnife]

That truss is built incorrectly. The design puts excessive down pressure on that bottom member that's supposed to be under tension. Google pictures of trusses and notice that the angled braces on either side of the vertical center support always go from center of the bottom member to a point midway on the upper cord, which is the opposite of how that one is built. How many trusses are there in this building and what is the span? Looks like about 30 ft. wide?

 

[etpm]

Why not just lash another beam along side ? Be done with it. If the wall has pushed out. Pull it in. The building seems shy of enough vertical roof support. Maybe even another truss on each side, appropriately spaced.

To assist just the one beam, with no consideration for any other part of the structure, I think your solution is the best. Assuming, and this is a big assumption, that every thing was built to code and this particular beam just happened to fail, perhaps just because it was persnickety and wanted to cause trouble, then adding another beam without removing the persnickety beam seems like it would be the fastest and least expensive fix. Just make sure the new beam will be able to properly take the load of the broken beam. It also may be advantageous to threaten the broken beam with a burn barrel so that it doesn't cause any further problems.
Eric

 

[2manyrocks]

I am grateful to the other members who have pointed out many aspects of this that I did not realize.

What is the distance between trusses in this building? It looks like the end wall truss is pretty far from the one that is broken.

 

[BlueKnife]

I am grateful to the other members who have pointed out many aspects of this that I did not realize.

What is the distance between trusses in this building? It looks like the end wall truss is pretty far from the one that is broken.

More than likely they're 10 ft. apart. That's the standard in the area where the OP and myself live. Waiting to hear from the OP on the width of the building, but if it's what I think it is (30'), he's going to have some potentially significant structural changes to make. There's not much use simply replacing the cord of the truss that broke since it broke due to a design flaw, not a flaw in the wood. It'll just happen again. The diagonal braces on those trusses are basically backwards and most of the problem. At minimum he should cut those out and get rid of them before replacing the bottom beam. It's possible he could get away with just doing that, but I'd be more comfortable with some more significant changes, if the setup of the building allows. Since it's already got a wall beneath it, that truss could be supported by a post up to the peak, essentially turning it into rafters. That'd work with the other trusses in the building too, but not (of course) if there needs to be full width clear span.