We are using termite resistant insulation on the exterior foundation of our slab with in floor heat home. The amount of insulation extending above grade will be  a little as possible , but has to be shielded from UV. I would like to cover it with a product that is durable and maintenance free.  Some have suggested using stucco, but I worry about staining. The termite shield extends over the top of the 2" styrofoam then 90's down a good inch which locked the sheets in well in place prior to back filling, but still has a little room . I would like to find a product   that is good for earth contact that is available in widths up to 12", that I could slip in between foam and shield lip on top, and back fill against the bottom to hold in place. Any suggestions?? Are there any adhesives that work with styrofoam ?

I used a product called "Prep coat B-2000" by Durock. It is a stucco like- parge coating designed for ICF's. You mix it with water, spread a thin base coat, then you apply a fiberglass mesh, wait for it to dry and apply a second coat. It's only been on for 6 months so I cannot attest to it's longevity yet, but it went on very easy. I might paint it eventually but I only have about 6" exposed between the ground and the flashing, and it looks good the way it is. (It looks like concrete).