Using a paddle-type Drias particleboard blender the face and core furnish were blended with 5% pMDI resin (based on furnishoven dry weight)for 5 min while both surfaces ofthe Flax and Hemp fiber mats were hand sprayed with 5–6% pMDI. To allow smooth resin flow and penetration into fiber mats the viscosity of the pMDI resin was lowered by mixing with acetone at a 50:50 ratio. After spraying the mats were left for 15–20 min to allow evaporation of the acetone. Teflon sheets were used as release agents to prevent direct contact between the caul plates and the resinated furnish and allow for easy removal of the final board after pressing. Mats were hand formed in a 635 by 635 mm forming box through a layering process—face furnish–fiber layer–core furnish–fiber layer–face furnish. The lower face furnish was first uniformly spread in the forming box and prepressed. The sprayed fiber mats were then evenly laid unto the face with 1 mm overlap along fiber edges. Next the resinated core particles were spread on the aligned fibers and prepressed. Afterwards the upper fiber layers were carefully placed unto the core furnish and evenly covered with the upper face furnish. The formed mat was prepressed and subsequently hot pressed at 140 ◦C for 8 min (including press closing time)in a Pathex press to a target board density of 620 kg/m3 and panel thickness of 12.7 mm.