Let $\Omega$ be a convex polyhedron in $\mathbf{R}^3$ with boundary $\partial\Omega$ consisting of $N$ polygons $\{\Gamma_j\}_{j=1}^N$. It's well known that in general
$$ H^s(\partial \Omega) \neq \prod_{j=1}^N H^{s}(\Gamma_j) $$
since the latter space says nothing about the behaviour of the functions at the edges and vertices of the polyhedron. I would like to know what additional compatibility conditions are required so that
$$ \left\{ u \in \prod_{j=1}^N H^{s}(\Gamma_j)\quad \mathrm{and} \quad u\,\,\mathrm{obeys}\,\, \mathrm{conditions}\,\, (...) \right\} = H^s(\partial\Omega) $$
I only care about the case $s=1$, but a reference for the more general case would be interesting to see. I know of a good reference for the necessary compatibility conditions for planar polygons, e.g. Grisvard's book Elliptic Problems in non-smooth domains (Th. 1.5.2.3). However, I can't find much in the case of polyhedrons in $\mathbf{R}^3$.