This study aims to strengthen single lap adhesive joints by reinforcing with sewage sludge ash (SSA). Micron size SSA was added to the epoxy adhesive at the rates of 0%, 5%, 10%, 15%, 20% and 25% by weight. First, 10-layer glass fiber/epoxy composite laminates to be used as adherent were produced, and then single-lapped connections were created with micro-particle added epoxy adhesive. The effects of SSA particles on the epoxy adhesive were investigated by tensile test. Depending on the tensile test results, the addition of ash at the specified weight ratios increased the shear stress.