Patent ID: 8414816

Claim:
A method of forming a building block comprising the steps of: a) providing a mass of straw stalks having naturally occurring binding agents; b) shaping the mass of straw stalks in a compressor having compressing walls by heating the mass of straw stalks under pressure in the presence of an added binding agent to form a building block that is vertically stackable for forming a load-bearing wall, said building block having at least one rigid and planar wall; and (c) forming at least one through-hole in the building block, the building block characterized as further including: i) a first wall having a thickness and an outer surface that is generally planar and smooth, ii) a second wall having a thickness and an outer surface that is generally planar and smooth, and being arranged in spaced relation from the first wall to define a pair of spaced apart opposing sidewalls from the first and second walls and so that the outer surfaces of the first and second walls are generally parallel with each other, and iii) an intermediate block portion sandwiched between the first and second walls, the intermediate block portion including the at least one through-hole aligned generally parallel with the outer surfaces of each of the first and second walls, wherein during the shaping step, a plurality of the straw stalks bind to each other by way of the naturally occurring binding agents and by the added binding agent, wherein the first wall, second wall, and the intermediate block portion are formed from said mass of straw stalks, and wherein the heat and the pressure are applied by said compressing walls at a temperature of about 175-425° F. and at a pressure in the range of 1250-2000 psi for approximately 20-30 minutes so that a localized density gradient arises within the block, said localized density gradient generating said first and second walls.