There are a couple of things i think;
first of all; i like the rusty pipe.
second;
The framework/window and the frontdoor , will look a lot nicer, i think , when they fall inside the wall (if you don't know what i mean i will make a quick sketch for you )
And last;
I'm going to bitch about the corner stone again
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I think that you should lower the vein width or remove the texture from the colorinput and put in the bump-input, and then add as i earlier suggested a fractal or something like that to the specular input