The properties of regioregular poly(3-hexylthiophene) (P3HT) thin layers prepared on silica surfaces are investigated by X-ray reflectivity measurements and a model independent fitting approach. As P3HT is a semicrystalline polymer Bragg peaks, corresponding to the repeating distance of lamella sheets, are evident within the reflectivity curves which are not describable with simple one- or two-layer models within a reflectivity simulation minimizing the accuracy of the data evaluation. In this work a model independent fitting approach is applied to be able to explain the entire reflectivity curve and to gain information on the internal structure within thin films. The thin layers were spin-coated from various chloroform solutions; solution concentrations (c) from 0.2 to 6.3 g/L resulted in P3HT layers with thicknesses (d) ranging from 3.7 to 64 nm with the layer thickness following a d similar to c(0.84) dependence. The model independent fitting approach reveals directed lamella order is present within the samples prepared from low concentrated solutions while for higher concentrations disorder within the electron density profile is observed.