When I say “interior cast stone” v/s concrete versions, sometimes this might be confusing, so I thought I would illustrait what I mean and define it.
By “interior” this can include a covered porch or entry as well as your livingroom, with this version of my work I use a variety of interior paints, stains and other media to get an aged look. These are just fine under a covered porch, sun and freezing cold doesn’t bother them at all.
However, placing an interior cast stone out in the garden, keep in mind that rain will be soaking it, snow, ice and if laid on the ground they absorb moisture. The first thing that would happen is the interior paints would come off after some time, then when the finish is gone the rain and snow goes to work on the matrix of the sculpture itself.
Below is a photo of an experiment I did placing 2 interior pieces right out on the ground in the rain and weather about 5 years ago.
The one on the left is my Public School gargoyle head No 168, as you can see the rain and wind has created an interesting aged “sandblasted” look like the rocks in the desert of Nevada or Utah;
The one on the right is a section of Art Deco panel 8B, it is in better shape, and this all took about 5 years in Midwest harsh weather to accomplish.
Exterior concrete will not do this, that is why I use concrete for exterior casts, and it gets a special acid stain FOR concrete which does not fade, or peel in the weather.
So I let clients choose, if you wish to place an interior piece outdoors for some reason, order the Old Limestone Grey finish, and maybe apply some Thompson’s water seal to it once a year, and it should do just fine for at least several years at least, more so if placed so heavy rain doesn’t pound down on it as happened to the 168 head.
But for long life, choose concrete for the garden.