Adding insulation pellets to cob

I just started reading Becky Bee's book about cob houses, and she makes a casual throwaway reference to adding Styrofoam pellets to cob to increase its insulative properties.

Can't find any other info about this online. Does anyone know if it would work? Would it compromise the strength of the wall? Would you only add it to the outer portion of the cob wall? If it worked in cob, would it work in earthbags?

Or has anyone used an alternative kind of insulation in cob - pumice, perlite etc?

Thanks!

Cob is pretty forgiving. If you kept your Styrofoam pellet percentage to less than 20% of your mix I don't think there would be much of loss in compression strength. Regarding insulative value I think it would be minimal. I would throw Styrofoam pellets into my cob or earthbag mix to make use of a waste product rather than for the insulation.

I am with Aaron, insulation needs to be a continuous membrane or unit.
Separate balls would not do anything.
You have few choices if you want to use Cob and have an insulated wall in the manner expected by many today, they are almost opposites.
Alternatives ;
- use cob the way it has been used for centuries as a very thick solid wall with thermal mass.
- have two thinner walls separated by a continuous sheet / layer of insulation
- install a modern framed wall on one side

One advantage to mixing in styrofoam to your basic cob mix is that it weighs a bit less to handle.  That can make handling it a better proposition.  Think it may affect breathability, and drying time..

I worry about the life cycle impact of such a project.

Basic cob elements are generally inert. When you're done, you can remix them with compost and biochar and chicken poo and add them to your vegetable garden. No problem.

But there is no way to get shredded styrofoam out of the mix. It would have to be trucked to a landfill. Not a happy outcome.

If the weight of cob concerns you, quit the gym and start working with cob.
Start with small lumps and build up the volume until you get strong enough to not notice.
Ever tried to get a styrene ball out of your nose?
I have seen someone take years to blow one out!