Folks,
Sorry if this has been covered elsewhere, I looked but couldn’t find anything on it. I have a largish (50×30) completely unfinished attic. The ceiling height isn’t great (only about 8’ at the peak) but I can’t help but think about all that square footage going to waste.
Unfortunately, the attic joists are inadequate for a floor, only 2×6 on 24” instead of 2×8 on 16”. The joists are old fashioned true 2×6, aka rough 2×6 aka dimensional lumber. Some googling suggests this is equivalent to modern 2×8, but the 24” width is still a problem.
The span is 30’ but I have been vigorously assured by some professional carpenters that there is no way that’s a 30’ joist, that the center wall is certainly load-bearing. The outer walls are 3-course flemish-pointed brick. The load-bearing center wall is just framed, not brick. There is no existing staircase to the attic.
The architect I asked about finishing the attic was dismissive of the idea but wouldn’t go into details of why. I think he’s mainly thinking about more conventional architectural improvements and doesn’t have quite the thrifty mindset I have.
I talked to some friends more knowledgable about structural engineering than I about beefing up the floor, they said it’s not inconceivable but unlikely. In a nutshell, they said that the overall structure (no just the attic joists) can take a certain amount of load, what they referred to as a “mass budget”; any obvious approaches (sistering the joists, or one idea I had was laying down a double layer of 3/4” plywood) would add a lot of mass that might exceed that mass budget.
All of this has convinced me that doing a full finishing of the attic is a non-starter, but I’m still inclined to do a light, cheap finishing job; light paneling replace the current floor of pretty old and spotty clapboard flooring, add a few more lights, and put in a folding staircase. Maybe put in a light futon couch/bed or two, for skinny overnight guests :-).
I guess my question is, are there any angles to this I haven’t considered, or any techniques/materials that might make this more tenable?
-- "Always cut *towards* a major artery... that way you'll be careful."
