  A radiation transfer model for the top-layer of a flared dust disk around a
low mass star is presented. The disk structure, temperature distribution and
spectral energy distribution are compared with the results of the analytical
two-layer model of Chiang & Goldreich. We find that both, a proper iterative
calculation of the main parameters and proper radiation transfer calculations,
are important to not overestimate the disk structure and its emission
especially at long wavelengths.
