Tiny house built into a larger shell?

So take a crappy house,fix the shell,gut the interior,add three feet( random number) of insulation to every exterior wall, and finish the inside as you see fit.
You lose square footage,gain super insulation, and possibly avoid many permitting issues.
I am thinking wood chip clay slip for the insulation, steel siding and roof, and a cedar interior( ok, cedar interior is maybe a bit much)
So, is this unthinkable?
Or counter productive?
I just know there are structures for sale that are not worth salvaging by conventional means. This hermit crab approach is one idea for Making houses into sustainable homes.

William Bronson : Specifying a large building that has no Interior Load Bearing walls, The next question would be how to keep all that insulation Dry.

Even with tight control on water vapor production inside the house you are left with using a water vapor barrier and some kind of a Heat Recovery Ventilator
to purge the water vapor to the outside .

At this point you have your dry insulation and are living inside a plastic bag and are dependent on a mechanical device to pump out your dirty old humid
stinky air and pump in new air !

While I have greatly over simplified the Situation- the tendency to build ever tighter and tighter -very well insulated homes and the dangers to the houses
structure if excessive amounts of moisture do find their way into poorly sealed wall cavities can not be overstated

Take a look at the link below, This video should start at about 3:30 to review typical water vapor sources, The rest of the video is also worth your time, it was
made by the Good People at the Cold Climate Housing Research Center- an "Arm" of the University of Alaska- Fairbanks !. ( You and I know Cold ----

-They know COLD !!! )

https://youtu.be/h4RxZB8l8Eg?t=3m30s

A Rocket Mass Heater RMH that is actively running should exhaust a sufficient amount of high moisture content air andpull-in more than enough Make-up
air to greatly reduce the interior water vapor load !

However this cannot be the only source of air exchange Even though it cob portion of a Thermal mass is capable of cycling large amounts of water vapor,
absorbing vapor when the humidity is high and releasing vapor when the interior air is high - this could be easily augmented with simple fan but then you
are back to a mechanical device to adjust air quality !

Hope you enjoy the video - For the Good of the Craft ! Big AL

Too much insulation can cause structural issues- dependant on what your building is made from, what insulation you use, etc.

For example: where is the condensation point, inside the fabric of your walls? Can cause damp and rot problems inside the walls.
Structural problems, if you add feet of insulation do you have to move door ways or anything?

Are you worried about keeping warm in winter or cool in summer?

- heres a link to a '' Natural Ventilation'' Thread that reinforces the idea of the need for an adequate ventilation- irregardless of your homes size !


https://permies.com/t/42593/natural-building/Natural-Ventilation


for the Crafts ! Big AL

The huge (three foot ) amount of insulation was just pulled out of my ass, though I am led to believe that a "mass" style insulation would breath well, and avoid most issues with moisture, as long as it has a "good hat and boots".
The siding would just be part of the "hat".
This thread:
R-Value
was what I was thinking off when I proposed this idea.
The bits of this thread that propose two basically conventional walls with 1 foot of insulation in between made me think of using the existing walls of a crappy house.