Cut Wooden Roof Trusses 1

[TRAK.Structural]

See pictures below. Looks like a mechanical contractor just decided those web members weren't needed so they got cut out. Besides replacing the trusses with a profile that goes around the mech components is there another alternative repair? I'm thinking that a traditional rafter/ceiling joist system could be installed in these (2) bays. The process would be to replace the bracing members between trusses at the ridge with a 2x10 or 2x12 ridge board (size dependent on the rafter size needed). This ridge board would have to be fastened each end to the existing trusses. Add appropriately sized rafters on both sides of the ridge board at each cut truss. Add ceiling joists all the way across and connect at the rafter heels. Depending on the ceiling joist span these may need to be double 2x4's to fit under the mech unit. Not an easy fix but maybe easier than truss replacement. Any thoughts or other ideas?

 

[SWComposites]

Assuming there are existing ceiling joists,
- fill in the webs on the right side of the photos with plywood connecting rafters to joists, maybe on both sides of the existing cut trusses.
- on the left side, put a new ridge beam/header just to the left of the existing ridge filler boards, tie into adjacent trusses; sister in deeper rafters adjacent to the existing rafters at the two cut trusses and the adjacent two intact trusses.
- basically minimize the amount of existing material to remove; just add stuff.

 

[BAretired]

Determine who was the idiot who cut the members and make them pay for the repair.

 

[XR250]

Can you use an interior wall for support?

 

[TRAK.Structural]

SW - Not sure I see how adding a ridge "beam" works here. The beam would need to be supported at each end, presumably by the adjacent undamaged trusses, which were not intended to support additional load like that.

BA - I don't disagree, but who pays for the repair is going to be someone else's battle to sort out.

XR - Maybe, but I'll need to check the floor framing below the interior walls to see if there is extra capacity for this load path. Would you look to add a brace down from the ridge to the interior wall to mimic how the cut diagonal was originally functioning? I think to justify this approach I'd also have to run a quick truss model with the new support conditions and check to see if any significant increase in member forces are induced by the new load path. That's why I was considering trying to install a rafter/ceiling joist system to completely bypass the damaged trusses and avoid a more complicated (for me) fix, but I do like your idea.

 

[XR250]

Def. would have to model it to see if it is feasible. I imagine interior walls are currently providing the support.

 

[BAretired]

BA - I don't disagree, but who pays for the repair is going to be someone else's battle to sort out.

No, it should be sorted out now. The cost of repair includes the cost of engineering which, at the moment, is in some doubt. Preventing morons from cutting structural members without asking for approval is of prime importance.

 

[SWComposites]

The beam would need to be supported at each end, presumably by the adjacent undamaged trusses, which were not intended to support additional load like that.

Yeah, you may need to reinforce those trusses also, either with sistered members or plywood sheets. Just trying to throw out some ideas. Looks like a nightmare.

Was this discovered as part of a sale inspection? How long has the house been in this condition?