Roof Beam replacement.

[RobertEH]

I have a neighbor who had a bean on one of the truss’s in his shop break (allegedly due to snow load, but it happened prior to him purchasing the property).



I offered to help him replace it. The plan is:

1 Using the forks on the tractor, provide just enough upward pressure on the rafter to allow removal of the broken beam. We will brace the loader once we have the rafter lifted for safety.

2 remove the bolts in the fractured truss and replace with new wood

3 lower the forks so the roof settles in on the new wood.





Any faults with this plan?



In the photo, the red circle shows the broken beam, and the blue arrow shows the rafter we will put upward pressure on.

 

[Chewwy]

I have a neighbor who had a bean on one of the truss’s in his shop break (allegedly due to snow load, but it happened prior to him purchasing the property).



I offered to help him replace it. The plan is:

1 Using the forks on the tractor, provide just enough upward pressure on the rafter to allow removal of the broken beam. We will brace the loader once we have the rafter lifted for safety.

2 remove the bolts in the fractured truss and replace with new wood

3 lower the forks so the roof settles in on the new wood.





Any faults with this plan?



In the photo, the red circle shows the broken beam, and the blue arrow shows the rafter we will put upward pressure on.
View attachment 831893

Upward lift alone on the rafter does not appear to constrain the horizontal force of the rafter. The broken beam in tension constrains the horizontal force (inherent strength of a triangle) The upward force is provided by the vertical post.

 

[2manyrocks]

My suggestion is to use a mechanical screw jack or mechanical jack post for any lifting because it will give you the most control over the lift. It is easy to go too far with a FEL and cause more damage. A mechanical screw jack can't leak down, either, like a hydraulic jack while you are working on this.

 

[pmsmechanic]

If the beam on the other side is not broken then I wouldn't replace the broken one. What I would do is see is you can jack and pull everything into place. If you can then fill the joint with glue and clamp it till it's dry. Run a few GRK screws into the break while it's drying. After your sure it won't move then I would fill in with another piece glued and screwed beside the broken beam.

 

[etpm]

I don't know but suspect that there should be considerable force along the length of the beam. Applying upward pressure will probably tend to relieve some of this force but I have no idea how much. So I would try to remove any load along the length of the beam before I did anything else. Maybe use a come along with chains. Apply force with the come along until you can see the broken beam getting slightly shorter at the break. Then use some sort of mechanical means, like the screw jack previously mentioned, to apply vertical force. A hydraulic jack and wedges could also be used. I would not rely on a hydraulic alone, but would use it only for raising. I would avoid using the tractor. In this situation it would seem to be best to do everything slowly.
Eric

 

[ning]

+1 to the come-along - is there any sign of either wall not being vertical at that point or bulging outwards? Is the hip of the roof a straight line? Just wondering what ill effects have occurred due to the lack of that beam. If there's nothing to be seen then I'd try to just brace things (vertical jack + horizontal come-along tension) lightly without much movement
Looks like there's a web to the right, so that truss beam is definitely supposed to provide some vertical load and not just tension (thus, the blocks supporting it under the web).

What was the truss beam originally sitting on?
Is its mate next to it (behind it, in the pic) also broken or is that one handling most of the weight & tension for that region now?
Can we see a pic of one of the unbroken truss beams and where they're sitting?
Did someone put that vertical board that's next to the jack there to hold it up?

I suspect that if you're going to jack it up, you should probably do it at a point closer to the peak than where your blue arrow is since the load is coming from the peak.

 

[Streetcar]

Could be very bad plan.
Not a beam, but part of truss that is broken. Removing the broken tension member could cause the building to expand outward and collapse roof.
How long has member been cracked.
I would try to add reinforcements to existing beam rather than replace the broken member.
Can you take more picture of entire truss and broken section

 

[RobertEH]

Appreciate the thoughts. Has me rethinking some things.

Here is a photo of the full truss. the 6x6 to the left of center is just sitting there as a temporary brace. The "tree" just right of center was put there by the prior owner as a safety...

• I will have to go over and look to see if the beam on the other side is also broken or not. I want to say it is? but not 100% sure.
• I am not sure if the wall is bulging - not so obviously so that it jumped out at me, but worth checking.
• Beam/truss cracked under the prior owners care - not sure how long but it has been at least 2 years. I believe the temporary measures have kept it intact for quite some time.

I am unclear regarding what folks mean about using a come along? what would I be connecting each end of the come along to? Would I be pulling the base of the truss upwards towards the roof from somewhere near the center of the truss in an attempt to release pressure on the edges and potentially seal and sister some new wood alongside the broken boards?

 

[ning]

Probably loosen a wall panel or two on each side, put some tension between the two uprights - because the bottom beam of a truss is supposed to be in tension (the roof load pushes out, the bottom beam keeps the triangle from collapsing). That's why the question about the wall bulging outward.

Check the level/vertical of the posts at both ends of the broken beam.
As previously mentioned, if everything seems perfect (no bulging, everything properly vertical) then you should just get a little bit of tension on the top chords of the truss (the roof sloping parts) so that when you put in the new beam, and then relax that tension, it settles to how it is now. Obviously, if there's a bit of bulging, you want to slightly overcorrect that so that once again, when the new beam is placed and the tension is relaxed, it settles to how you want it to be, long term.

 

[RobertEH]

Gotcha. very helpful.

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