In this work, previously synthesized biopolyols were analyzed in terms of their rheological and thermal properties, very important from the technological point of view. For better evaluation of performed synthesis, the influence of its time and temperature on the properties of biopolyols was determined. In the end, obtained materials were used to prepare rigid polyurethane-polyisocyanurate (PUR-PIR) foams, to evaluate their potential application in polymer technology. Presented results fully justified conducting of synthesis in two steps. Biopolyols obtained after second step of synthesis were characterized by two times lower viscosity than polyglycerols resulting from first step. Moreover, their thermal and oxidative stability was noticeably higher and enabled their effective incorporation into manufacturing of PUR-PIR foams. Spectroscopic and microscopic analysis confirmed that foams were successfully obtained from polyglycerols and biopolyols, however, there were noticeable differences in the mechanical performance of prepared materials. Partial substitution of petrochemical polyol with polyglycerol resulted in the decrease of compressive strength, comparing to reference sample, while incorporation of biopolyols noticeable enhanced that parameter.