The study focuses on a life cycle assessment of a wood-based residential building and evaluates the magnitude of individual construction components—foundations, flooring, peripheral wall, inner walls, ceiling, roof, windows, and doors—in terms of climate change; acidification; eutrophication; photochemical oxidation; depletion of abiotic elements and fossil fuels; and water scarcity categories within the system boundaries of the Product stage of the life cycle. The assessment was done using the SimaPro software and the ecoinvent database. The results pointed at the advantages of mass timber as a construction material and highlighted the significance of the type of insulation used. Foundations were found to bear the highest share of impact on photochemical oxidation reaching nearly 30% and depletion of fossil fuels accounting for about 25% of that impact. The peripheral wall was ranked the worst in terms of impact on acidification and eutrophication (more than 25% of both), depletion of elements (responsible for 50% of that impact), and had about 60% impact on water scarcity. After adding up carbon emissions and removals, the embodied impact of the whole construction on climate change was detected to be 8185.19 kg CO2 eq emissions which corresponded with 57.08 kg CO2 eq/m2 of gross internal area. A negative carbon composition of the construction was also set.