It is mediocre quality of work and ABSOLUTELY NO warranty whatsoever.
I got my front steps (made by them) distorted and my unistone sidewalk collapsed. Neither was repaired. Moreover, Sergio never told "NO". It was kind of "Yes! For sure we will fix it! Give us another month to finish a current project, please!". And it is 3 years like this.
So, go with them only if you save $5000+ which you can pay to somebody else for reparation later. Or, even better, do not consider SJ as your contractor.