The paper presents the issues related to the excessive use of natural resources and the possibility of its reduction through the use of ash deposited in landfills. Two different ashes from the combustion of various types of biomass (coconut shell and sunflower) were used and compared with each other. As part of the tests, the chemical composition of the ashes used was checked and samples of cement and standard mortars were made using the two types of fly ash. The research shows that the chemical composition is similar to the volatile chemical composition of conventional burning pavilions. It should be noted that the type and origin of the ash used for the results obtained is important. The use of ashes as a partial substitute for standard sand increased the compressive strength of all tested samples from 1 to over 17%. Ash additions reduced the compressive strength drop after frost resistance testing by 3 to 15%, and slightly increased the absorbency by 2 to 6% relative to control samples. An important advantage is that the use of ash as a substitute for standard sand allows you to reduce the consumption of natural resources.