Finally, the increasing of gypsum percentages from 0% to 10% caused thermal conductivity to increase from 0% to 48.7% in comparison to brick materials without gypsum and with 3% wheat reinforcement fibres. For barley straw fibres, increasing gypsum percentages from 0% to 10% caused thermal conductivity percentages to increase from 0% to 51.6% with the same fibre content.