WTF? Did my contractor critically weaken my floor? 2

[NuclearNerd]

Must control anger....

I'm building a bathroom in the attic. When planning the job, my contractor suggested I'd have to cut and reinforce the floor joists to make way for the sanitary pipe. I told him he could go under the floor joist, as there is a chase below (above a 2nd storey shower).

Today I arrive home and I see he's gone ahead and cut the joist (joists. 2 actually) anyway. He's "reinforced" them with a cantilever arrangement shown in the attached photo. I haven't done a full analysis, but the joint does not look kosher to me. Can someone here tell me I'm worrying too much, or if not, tell me how I can repair the damage?

For background, the original attic floor joist (real 2x6) sits on the brick exterior wall (under the foam at right) and the center wall of the house (off to the left) for a total span of about 10'. The joist also holds up the knee wall shown, which transfers some of the load down from the roof. I thought it must also tie the roof rafters together, but I don't know how since it isn't very well attached to the joist which spans the other side of the house. Obviously this beam carries a complicated set of loads - I don't think a little 2x4 hanger is adequate to transfer them all!

More photos here:

http://www.flickr.com/photos/28928816@N00/sets/72157625395689324/

 

[Ron]

His reinforcement is worthless. At this point, you need to put a steel reinforcement plate UNDER the pipe and on both sides of the joist. Extend to at least 300mm on either side of the cut. The plate should have a "U" shaped cutout to conform to the pipe and be bolted through the joist, thus clamping the joist on both sides. Use 4 bolts, 12mm diameter ea., on each side of the pipe. The steel plates should be at about 4mm thick, each.

 

[OHIOMatt]

The contractor has certainly weakened the floor substantially. The cut and "repaired" joists have virtually zero bending capacity at this time.

Without knowing for certain what the loads are, I would sugget that you attempt to place new joists back that would have equivelant or greater capacity. If possible, going into the chase as you suggest may be the best bet.

Sorry, not much on the fix, but my opinion is that you do have an issue that should be adressed.

 

[MiketheEngineer]

Ask him to seal the fix with his engineering seal. OH - he doesn't have one?? Then ask him where he got his engineering degree from...a match book cover or on-line learning place.

At this point - he will probably want to slug you. So be it.

Tell him:
Take out the drain
Replace or sister the joist - BTW 2x6's might be marginally OK in this app - probably not.
Replace drain in crawl space as you suggested.
Don't pay him until the work is done correctly.
If you pulled a permit - tell the inspector what was done and have him FLUNK it.

You got screwed.

 

[NuclearNerd]

Thanks all. That's what I thought. F.

The plumbing will be rerouted under the joists. But repair is going to be tricky. I've covered the outside wall in foam, so I can't lay new joists without considerable demolition. Do you think it's at all possible to splice the cut with 2x6s on either side? If so, where should I look to calculate the overlap and the number of fasteners required?

 

[Ron]

It is possible to splice 2x6's on each side; however, it appears that you have limited access and length to do proper wood splicing or sistering. For that reason, I would use a metal plate repair (flitching) on each side of the cut 2x6. Cut a piece of 2x6 to fit in the gap. Extend the plate at least 12 inches beyond the cut in each direction. Use through-bolts to attach and use a pattern of at least 4 bolts on each side. The bolts should be 3/8" to 1/2" in diameter. Bolt at least 2 bolts through the fill-in piece.

The in-filled piece does nothing for strength, it is just there to be a "wedge" against deflection.

 

[rscassar]

I just looked at the photo but:

Yes, it doesn't look good.