This article deals with thermal properties of selected kinds of timber. Wood, generally, is one of often used natural materials in building structures. For our research, woods were selected according to frequency of utilization in civil engineering branch. Four different timbers were chosen, and experimental determinations of their properties were performed. Basic physical properties as well as thermal properties belong among studied characteristics. From achieved results, it is obvious, that the bulk density of studied wood ranges between 373 kg m^-3 and 649 kg m^-3, the open porosity differ by 13%. Regarding thermal properties, values of the thermal conductivity as well as the specific heat capacity are influenced mainly by the open porosity and moisture content. The thermal conductivity in dry state varies by about 31% while in the case of the specific heat capacity the difference is about 19%. Obtained date will be used in the mathematical analysis of heat transport in building structures.