Wrestling with thoughts on home repair
I'm thinking through some home repairs I have agreed to do for my daughter next week. Normally, these things would not be a big deal, but the last such effort started as a replacement of a floor in her back room, and ended with pouring a foundation for a bearing wall that had none, filling a crawl space with gravel so I could pour a concrete floor and buttress to keep the house from sliding to the south (it had moved/collapsed about 6"), replacing failed joist systems and sub-floor (particle board sub-floors ought to be a hanging offense), and replacing the plumbing and wiring in that end of the house (what do you say when you see a 10-3 with ground wire, still connected to the box on one end, and lying loose in a crawl space secured with some electrical tape). So, the work is replacing a bay window and putting in additional joists under the kitchen, but the likelihood is there will be home repair adventure involved.
The part that has me thinking is the joists.
Right now, the kitchen is supported by 2x10's, 24" OC, 14' long. By any measure, that is inadequate. The right thing to do is to sister 2x12's to those 2x10's, and add another 2x12 in the middle to create a 2x12, 12" OC joist system. There will be some pulling out of plumbing and wiring needed to put those in, but the old stuff is pretty bad anyway. I'll let the subfloor go for now, just supporting it with patches scabbed in between joists, and wait until we tear out the kitchen floor to replace it all.
The daylight basement that new ceiling will intrude into is finished. It has a bathroom and a lot of space. The previous owner used is as a professional office which included a couple of employees, and it was very adequate. Certainly, preserving that use will preserve value in her home when it comes time for resale. I'll be tearing it all out of course, but the new ceiling height will be 2" lower in the area under the kitchen. I don't lightly add an unsightly bump in the middle of the ceiling.
The alternative is to use 2x10's. That's probably still within code when they are 12" on center, but will they be stiff enough to let her put in a tile floor (which she wants to do) and carry the weight with enough rigidity to keep the grout in place? I am inclined towards skepticism.
Does anyone have any thoughts on this beyond, "When in doubt, build it stout"?