[Cob] Cob ???? and an old cement block building

[Urban Arcadia]

Hi,
I have been lurking a while, thinking to build something natural in the form
of strawbale / cob for about 10 years and finally getting moving.  At this
point I am also enamored with a building that has come up for sale near me,
and thinking to combine the two options.

It is a cement block building that housed a Catholic school and convent
years ago.  It is where I went to elementary school.  It has a funny
residential zoning but could be turned into a duplex, which would give me a
place to live and some income, eventually using it entirely for income while
I move on to a freshly built natural building, out in the sticks someplace.
This building as it sits is a horrendous eyesore, covered in vertical wood
siding, and since historical restoration is my first passion, it is too
tempting and too sentimental to pass up.

My question is, at this point I assume the building is poorly insulated if
at all, and will need a lot of work to become anything resembling energy
efficient.  It has very high ceilings in some parts (I believe because of
the layout that possibly the section I remember as a school was first the
original church, but have not verified that yet.)  It also is over 4000 sf,
so there is plenty of space to build almost a new set of walls inside and
insulate between them.  Does anyone have a suggestion for this?  There is
basement under SOME of the building but I believe half of it is on a slab.
Need to go check that again to be sure.

What I am wondering is possibly some sort of cob ???? walls inside with
maybe insulation of straw bales between them and the cement blocks.  Any
ideas for all this?  Or other suggestions?  (Besides walk away fast)  There
is not room on the lot to re-build walls outside the cement blocks, but
there is definitely room inside.

Thanks for any suggestions,
Sabrina Free

"The world breaks everyone, then some become strong at the broken places."
Ernest Hemingway, "A Farewell to Arms"