I was forced into renovating a second floor bathroom for numerous reasons. Never having liked the layout, I thought this was a perfect time to change it. The room is 70" wide by 126" deep. I wanted to put the vanity on the left wall, the toilet next to the vanity and then the tub on the back wall, drain to the left, so the left wall would become a wet wall. Problem was, the joists ran across the room, not down. Putting the toilet on the left wall would force me to bore 4" holes through 2"x8" joists. The two joists to be bored would sit directly under the tub. A real no-no. I did a little (clearly, not enough) research on the internet & mostly talked to some local building supply stores. I had an idea that laminating (glued & screwed) 7 1/2" X 30" strips of 3/4" plywood to both sides of the joists might provide enough support that the joists could then be bored. And this is where I was ill-advised. I was assured this would provide enough support, and that with 3/4" ply subfloor followed by 1/2" cement board the floor would be solid enough to support the tile I wanted to install. After completing this portion of the renovation and replacing the subfloor, another trusted advisor spoke up and said that I can't do that. I've since stopped the renovation in order to take the time to figure out what to do so that the plumbing and floor support will be safe and to code; hence, my now having found this thread. As an FYI, in doing my second round of research, I stumbled across these metal joist reinforcers - http://www.metwood.com/products/reinforcer . They look like just the thing I need to solve my support issues, assuming I leave the bathroom in it's current configuration. The problem with them for me is that they cradle the bottom of the joist and I don't want to have to tear up the first floor ceiling in order to install them. So, one of my questions for all you engineering gurus with your mathematical wizardry is, if I were to attach 30" long strips of 1/8" or 3/16" steel strap to both sides of the joists, both above and below the holes, do you think this would provide enough support for a full tub of water and a tile floor? If so, how would you suggest fastening them? Should they be screwed independently to each side, or bolted so that they sandwich the existing laminated joists? Further, should I be using some form of glue or cement to 'laminate' the strapping to the bulked up joists (not that I'm aware of any metal-to-wood adhesive)? Another option I have is to remove one side of the plywood lamination I've done. Then sister both existing joists with a new (at least 6', but as long as possible) joist that has one of the joist reinforcers listed above attached. Due to the construction, the joists are fully supported by a bearing wall on the left side of the washroom so these new sistered joists would have the benefit of being supported on one end. Any thoughts on any of these potential solutions? Thanks in advance for anything shared.

When a floor joist deflects downward, the bottom fibers of the wood joist are put into tension, in effect, they are stretched while the top fibers are compressed. Screwing a steel strap to the bottom of the joist helps the joist resist the tensile load. It's the same reason why I-Beams are shaped that way, the flanges resist the tension (bottom) and compression (top).

I don't think that steak example is parallel at all. And given that it is *not* that hard to do, why not tell them what they need to know, so they -can- do it themselves? Or, maybe it is parallel. It's not -hard- to figure out how to eat a steak for the first time, but a person who had only eaten lasagna or cooked grilled-cheese sandwiches might benefit from a little extra info. Would you seriously suggest that a person hire someone else to feed him a steak, or would you just say, "Plastic would work, but it'll be less frustrating if you use metal. And it'd be easier with a steak knife instead of a regular table knife." Would you seriously say, "You obviously don't know enough to cook a steak; go to a restaurant"? Or would you say, "Use X flame, X minutes; you can tell it's by when it feels like this. Don't poke it with a fork to turn it, and don't use tongs; use a spatula to flip it so you don't squeeze the juices out." People who have cooked one simple thing are sensible to ask for expert advice when they're ready to expand. But wanting (or even needing) advice before doing so doesn't mean the person isn't capable of doing it successfully. And there are supportive ways to tell someone that you suggest they get someone w/ more expertise to help them. There was a beautiful example of that elsewhere on this forum. But I think that the level of detail given by people here and on the other thread on this topic, and the disagreements on this thread, are proof that this was a very sensible question to ask, and it in no way indicates that our OP is unable to hammer a nail or drive a screw. Or that the OP is unable to successfully support this notched beam. It's not that hard; but there are smaller pieces of info that will make the OP much more effective at this. If a person is just ridiculed for ever wanting to learn how to do things like this, how will they ever expand their abilities? Isn't that the purpose of forums like this, to transfer experienced knowledge to the brains and lives of those who are inexperienced but willing to get more info?

I was able to get it fixed without a lot of extra work. I appreciate all the responses, so thank you very much for that. As far as what I did: My son stayed above while I crawled under the house. I used a bottle jack beneath the broken floor joist (it's 2x4, believe it or not) I will be beefing it up with sister joists. Anyway, as I jacked up the floor, my son lowered the jack upstairs. I was able to get a new 2x4 sistered against the original one and placed a block and post to support it. Since then, I have replaced the original post with a 4x4 post, and built a wall off of that. The floor deflection is gone. The wall spans almost 4 feet along the side of the stairs. The joist below the floor is supported in the middle (under the original post) and 2 1/2 feet on either side by a girder beam.