To address the large house-building demand in developing countries, soil can be used as an alternative building material because of its high availability as a source material, its ease of processing, and its low environmental impact. In this work, soil-cement blocks (SCBs) with three different contents of mineral wool waste and soil-cement blocks with three different contents of sisal fiber were fabricated, microstructurally characterized, and tested after curing for moisture absorption, abrasion resistance, compression, bending, and accelerated erosion. An increase of 29% in compression resistance was found when 1% of mineral wool was loaded into the SCBs, whereas an increase of 0.1% of sisal fiber lead to a 20-fold increase of the rupture modulus (MR). From the results it is observed that both bending strength and compression resistance increased with the addition of mineral wool waste and sisal fiber.