Innovative use of giant reed and cork residues for panels of buildings in Mediterranean area

•The giant reed and the cork are good natural insulation materials and their use is an excellent solution to reduce agricultural waste.•The saved energy by the use of agglomerated cork walls for the envelope of buildings is more than 75% of the energy spent than building with brick walls.•The environmental effects of the disposed wastes of building components in giant reed or cork are lower than other building materials.•CO2 production for heating and cooling the building was: 2517 kg for brick walls, 623  kg for cork walls and 1905  kg for giant reed walls.