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

 

[pmsmechanic]

I personally wouldn't bother with an engineering review. What are they going to tell you? That the trusses suck? You already know that so why bother spending the money.

After some of the comments here and after having a good second look at the pictures I've changed my mind. You could replace/repair the broken parts but you still have a truss that sucks. The way they are bolted together is just an invitation for future problems. I can well imagine that someone thought they were building a super strong truss by bolting it all together but all the bolts are accomplishing is to concentrate all the forces onto a small portion of the wood. A good example of this is how the peak is overlapped and bolted together. Each side of the roof "truss" should be butted against each other, not overlapped and bolted. If you enlarge the picture and closely examine the truss you can see examples of poor design all through the truss. Joints overlapped and bolted where they should be butted and joined properly is just one example along with others mentioned by previous posters.

I believe the owner is going to have to come up with a plan to replace the trusses with something that will last or remove the roof and start over. Anything less will over time result in a collapsed building. The only other solution would be to add posts to hold the roof up but really that's only a mediocre band aid.

I can see an engineer looking at this and recommending a way overbuilt solution just to cover his/her butt. Not because the building needs it but just because! But truth be told what you really need is to replace all of the home built trusses with engineered trusses that will properly transfer the forces involved to the posts.

I would be very careful about getting an engineer to examine the building. You don't want them to all of a sudden complain to a zoning/permitting authority and have the building condemned. Just because!

You could take the pitch of the roof/span/rafter spacing information etc. to a rafter manufacturer and have them build you proper rafters. It also wouldn't be a difficult job to remove one rafter at a time and install an engineered replacement. The way the building is built you could prop up one rafter and replace it and then prop up the first rafter and replace the second one. It would really help to have an experienced contractor with that part though.

These are my thoughts on the subject based on what I see in the pictures. If I saw the building in person I could very well think differently. And ya I'm kind of hard on engineers but that's another story.

 

[RobertEH]

OK - we did the repair and lived to tell the tale.

• First we jacked up the broken end of the chord so we could removed the split support on the wall post with a new 2x6 that ran from the chord to the floor. In hindsight we should have used a 2x8 so it would have also supported the two sister's we added - this can easily be done later though.
• Next we compressed the split cord with liquid nails in the cracks to seal all that up. we held it in place with some clamps
• Then we cut a sister chord and screwed it in with treated decking screws the the compromised chord.
• We then repeated this for the split chord on the opposite side - it was in far worse shape than the visible one in the photo. It had been fully compromised and was providing little value to the strength of the truss.
• After that we ran three bolts clear thru the 10 foot set of sisters and trusses - filling the gap between the original chords with some 2x10 spacers.
• The final step in the repair was to add one more 2x6 to the wall post to support an existing rafter support on the truss - also running that to the ground.
• This completed the truss repair. We were able to remove all clamps and jacks and it all held quite well.

The final step was to remove the "tree" that was near the center of the truss and replace it with a 6x6 treated post - the tree was showing significant cracking as well. Unfortunately putting it dead center in the truss would not be possible without re-doing an existing wall under the truss. We settled for offsetting it and putting a block between the center of the truss and the existing wall.


The long term plan is to replace the metal (probably next summer) to fix some leaks and at that time add some engineered trusses to beef up the roof. This was built in the 80's so it is pretty old and could stand a new roof.

Thanks to all for the advice. The plan we put in action was largely based on the feedback here as well as from a buddy of mine. I learned a lot with this project!

Some photos

 

[ning]

Looks great!...
My only concern is that the bottom chord of the truss is supposed to (be able to) provide tension to hold the walls in, and I'm not sure how much of that chord is attached at the (previously) broken end?

It seems that the main compressive bolt is pretty much right on the crack, though I think I probably see a number of 16d nails as well, we all know what they're nailed into isn't likely to help a lot in the tension end of things.

I think if you really want it to be a long-term fix, you may need to use a steel rod attached to each end with something like a turnbuckle in the middle to provide tensile support (many old buildings in my gold-rush town have something like that to help stabilize old rock & brick walls) - that said, given the lack of any bowing in the structure, one could just say "doesn't look like it needs it" - until it does.

 

[EddieWalker]

OK - we did the repair and lived to tell the tale.

• First we jacked up the broken end of the chord so we could removed the split support on the wall post with a new 2x6 that ran from the chord to the floor. In hindsight we should have used a 2x8 so it would have also supported the two sister's we added - this can easily be done later though.
• Next we compressed the split cord with liquid nails in the cracks to seal all that up. we held it in place with some clamps
• Then we cut a sister chord and screwed it in with treated decking screws the the compromised chord.
• We then repeated this for the split chord on the opposite side - it was in far worse shape than the visible one in the photo. It had been fully compromised and was providing little value to the strength of the truss.
• After that we ran three bolts clear thru the 10 foot set of sisters and trusses - filling the gap between the original chords with some 2x10 spacers.
• The final step in the repair was to add one more 2x6 to the wall post to support an existing rafter support on the truss - also running that to the ground.
• This completed the truss repair. We were able to remove all clamps and jacks and it all held quite well.

The final step was to remove the "tree" that was near the center of the truss and replace it with a 6x6 treated post - the tree was showing significant cracking as well. Unfortunately putting it dead center in the truss would not be possible without re-doing an existing wall under the truss. We settled for offsetting it and putting a block between the center of the truss and the existing wall.


The long term plan is to replace the metal (probably next summer) to fix some leaks and at that time add some engineered trusses to beef up the roof. This was built in the 80's so it is pretty old and could stand a new roof.

Thanks to all for the advice. The plan we put in action was largely based on the feedback here as well as from a buddy of mine. I learned a lot with this project!

Some photos



View attachment 833010

I think that you really need to add some plywood to the end of your truss. If it was mine, I would cut a triangle shape out of some 3/4 inch plywood that would cover tie the boards together. I would use PL Construction glue because I think it's a lot better then Liquid Nails. Then I would nail it in a pattern similar to the red dots on the drawing that I did. I would do this on both sides of the repair, and then at every end of every truss.

 

[BlueKnife]

Looks great!...
My only concern is that the bottom chord of the truss is supposed to (be able to) provide tension to hold the walls in, and I'm not sure how much of that chord is attached at the (previously) broken end?

The tension on the bottom cord is from the two top cords of the truss essentially pushing towards each other and trying to sag. A properly connected center post eliminates that tendency to sag, thereby eliminating any tension on the bottom cord. If the OP's neighbor was to run that post to the top of the truss, so that it resisted side to side movement, he could completely remove the bottom cord. At that point, they would have converted trusses into rafters.

 

[CliffordK]

The plywood is one option.

My barn has some diagonals going from the top of the truss, down across the cord, and down to the post. Perhaps 4 or 5 feet down the post, and a half dozen feet across the truss. It is high enough that it really doesn't detract from the space in the barn.

Anyway, it would help hold everything together, and transfer some of the weight mid-span down to the post.

I can try to get some photos tomorrow.

Hmmm, how many trusses does the OP's shop have not counting the two ends?

 

[BlueKnife]

The plywood is one option.

My barn has some diagonals going from the top of the truss, down across the cord, and down to the post. Perhaps 4 or 5 feet down the post, and a half dozen feet across the truss. It is high enough that it really doesn't detract from the space in the barn.

Anyway, it would help hold everything together, and transfer some of the weight mid-span down to the post.

If designed and built properly, there is zero weight, other than itself, bearing on the bottom cord of the truss. It's being pulled straight to the sides, not down. The OP's fix should work, because the post that they used took all of the stress off of the improperly designed and braced bottom cord. That bottom cord is no longer supporting anything. If they moved the post to the center, they could remove the bottom cord entirely, converting the trusses to rafters.

 

[RobertEH]

Thanks all! I will pass all this info along to him for consideration. I think he is happy with where it is at for the short term, and he will make further corrections once he pulls the roof next year (more trusses, etc)

 

[BlueKnife]

Thanks all! I will pass all this info along to him for consideration. I think he is happy with where it is at for the short term, and he will make further corrections once he pulls the roof next year (more trusses, etc)

What you've got there should work fine (on that truss. He may have problems with the others in the future). Should he later on decide that he wants easier access to that loft, he can always put a post in the center, up to the top of the truss and remove the bottom cord.

 

[EddieWalker]

I would not remove the bottom cord, or any other part of the truss, no matter what else is done in there.