Roof Beam replacement.

[RobertEH]

I like the idea of strategic ratchet straps while we are working.

 

[RobertEH]

Actually I do have a photo of what I was describing from the first visit.

You can see the 2x6 I mentioned below the chord. It has split where it was nailed to the wall post (old nails in the two blue circles) allowing the chord to shift down.

I said above we would be replacing it with a 6x6 but that does not actually seem possible without removing the wall. I suspect once we get into it we will need to slide a 2x8 into that slot that runs from the base of the chord to the floor.

 

[ning]

I will try to get a photo (since it is not my place, I can't just saunter out and get one!)

At this point, I concur with everyone, we don't want to remove any of the old truss and that is not in our plans. Just re-enforce it and sister it together - adding two more 2x10's to the cord, and putting a 4x4 post under the wall edge of the cord where the former 2x6 failed. Keep it simple and as was said in an earlier post, kick the can down the road until he can have someone qualified look at it!

A+ idea.
Is there any chance of something big suddenly hitting the roof again (assuming that happened before)? Or is it just a snow load from here on out?

 

[RobertEH]

I believe this was all snow load (it was however broken before he bought the property). I did not see any evidence of an impact on the outside in that area though.

 

[ning]

Actually I do have a photo of what I was describing from the first visit.

You can see the 2x6 I mentioned below the chord. It has split where it was nailed to the wall post (old nails in the two blue circles) allowing the chord to shift down.

I said above we would be replacing it with a 6x6 but that does not actually seem possible without removing the wall. I suspect once we get into it we will need to slide a 2x8 into that slot that runs from the base of the chord to the floor.
View attachment 832462

How was the chord originally attached in with the rest of the truss? was it sandwiched at the bolt to its left (unsurprisingly in line with the break/crack) or is there another (single?) bolt hiding behind the insulation that it was attached to? I think I see the main vertical 6x6 or 8x8 post extending past where I expected to see the horizontal chord going out to.
Are the new 2x10 chord pieces going to attach to the columns, or where are you planning to put them?

 

[CliffordK]

The board on the side of that 6x6 is also split where the bolts go through it. I can't tell if you have access to both sides of the both of the bolts, but that would be a board to replace too. You can extend those support boards quite a bit longer, even all the way to the ground.
I had wondered why that board in your post #42 seemed narrow, now I see the split, and how the cord rafter has dropped by a few inches compared to the other end.
I always like to stagger bolts, nails, screws, etc, just a little bit, so they're not following the same grain.
If you do decide to marry a second cord 2x8 or 2x10, or even 2x12 to the outside of the broken one, I'd get some very strong wood glue (epoxy?), and try to repair the broken one the best you can before you attach the second 2x10 to it. Even glue them both together. And make sure it is all well supported. It will probably be cut into a wedge shape below the rafter.

Your profile lists "Idaho Panhandle". My father grew up in the Stibnite/Yellow Pine area. Apparently they got LOTS OF SNOW!!! It would need to have significantly greater load bearing than we have here.
I'm surprised you don't have a much steeper roof overall to shed the snow better.

 

[CliffordK]

Nail plates are also very common for merging members on trusses. I've never tried installing one, and perhaps they're installed with a press rather than a hammer.

 

[Streetcar]

I would like more pictures of the truss to post connection.
From your pictures the split 2x6 on the column looks like a temporary piece used during construction. Did lower chord break through support bolts. By design the lower chord should not have bending stress to break the way it failed

 

[BlueKnife]

I'm surprised you don't have a much steeper roof overall to shed the snow better.

That's a common sentiment here (I'm in North Idaho as well). Steeper metal roofs and insufficient insulation and ventilation allow poorly designed buildings to stay standing longer than they otherwise would. The truss that we're discussing is designed such that the diagonal braces are directing much of the weight of the roof down on the lower cord of the truss. They're literally doing the exact opposite of what they should be. That lower cord isn't supposed to be bearing any weight from the roof at all.

 

[etpm]

DO NOT REMOVE MEMBERS OF THE TRUSS WITHOUT ENGINEERING REVIEW. This could lead to collapse of truss.

This statement, the statement above, is vitally important. This is why in my post

Couple updates:

• The shop is approx. 50 feet long, and 30 feet wide
• There are 4 sets of struts about 12 feet apart
• The cords are made from a pair of 2x10's
• Both sides of that one truss cord are fractured

It looks like there was an ~18 inch piece of 2x6 nailed into and parallel to (as in vertically oriented) the 6x6 wall post. The truss cord butts to the wall post and rests ontop of the 2x6 giving it additional support.

The 2x6 failed (splitting along the grain where the nails attaching it to the wall post were). The truss cord has slipped below that under the edge of the truss


So the plan of attack now is to try to shore it up to the best of our abilities, and then have someone look at the entire roof and make some recommendations.
1. we will try to compress the 2x10 cord and compress the gap in the split as best we can
2. We will remove the failed 2x6 from the wall post and replace it with a 6x6 or similar that runs from the cord to the ground
3. we will then sister in a couple of 2x10s along side the split chord to stabilize it
4. We will replace the "tree" in the center of the truss with a 6x6 or similar.

That should help considerably and then we can look at other options with an engineer.

Appreciate the insights - we don't know the physics of this terribly well so I think it is best we move with this more conservative approach.

I would like to reiterate what others have posted. Do not remove any of the existing structure without first making sure you have already placed supporting members. Also, and this is just my opinion, I would not use ratchet straps. The reason being that they stretch. Whatever you use to take the load of the failed members of the truss should not be able to stretch or compress. When the load is changed as stuff is removed it would be bad if things moved. It seems to me that the damaged truss should be stabilized and unable to move before any repair is done. A ratchet strap under tension could pull stuff once a load is removed. A chain and/or cable will not move like a ratchet strap. Just my opinion of course but if this was my project I would make sure everything was in the proper place and nothing could move while repairs were being made. I know it takes extra time but it sure would suck if things moved and somebody got hurt.
Eric