Hello.

I am remodeling a bedroom above a tuck-under, 16x20 garage. I have it pretty well gutted at this point. I have a few concerns and problems, however:

1. Floor joists are 16' span, 16" OC, 2x6's. Floor is quite bouncy. (I posted about this a half a year ago, but haven't solved my problem(s) yet) The floor joists run transverse to the garage below, which probably rules out an intermediate beam, unless I used some special joist hanger to tie it into the garage door header (which may not support the extra load).

I should sister with 2x10s to get L/360 deflection, but I don't have this kind of space to work with - only about 2-2.5 inches to the garage door rails. I have thought about an 1/8" steel strap on the bottom of the joists (as recommended by brickeyee), or sistering with a 2x8, or maybe 2-2x4 sisters (on the sides of the lower portion of the 2x6's), or even a flitch beam (labor intensive).

The joists have drywall on the underside, and I don't know if I want to take on this reinforcing project at this time, with winter fast approaching. I have thought I would fix this problem "later", but if someone came up with a miracle solution, I am open to it...

2. Rafters are 2x6's, and I could use about R-49 insulation here in SD. I have flirted with furring out with 2x4s, adding layers of r-15 batts, plus a ventilation chute made of 3/4 foam insulation, for a grand total of about R-35. We would also use 6 mil. poly vapor barrier. I have also thought about multiple layers of pink extruded polystyrene, to the tune of about R-40 (a bit expensive, though), and also spray in isocene foam (I would assume most expensive of all) Thoughts?

3. We have thought of using grooved engineered siding (4x8 sheets) for the interior wall finish. This has its drawbacks, cost, labor, etc. We are now thinking of using 1/2" drywall, taped and textured. -- My only concern about the drywall is the potential for cracks to develop?? due to the problem with the undersized floor joists. Is this a valid concern??? other thoughts?

4. One final one - The window on the south wall has no header - only a 2x4 on weak axis where a double 2x6 or 8 should be. It is about a 4.5' wide opening. It is a bearing wall, the rafters tie in just about 6 inches above the window. The only saving grace, I think, is that the top plate just inches above the window, is a double 2x6. I don't think it is correct. However, the window opening and room have been in existence for about 55 years. Thoughts?? I guess I could reinforce the 2x4 with a steel angle or similar (I really hate to rip out framing at this stage)

Thoughts on any of this mess? Any help would be much appreciated....