Low-carbon building materials are attracting enormous attention due to the massive energy consumption and carbon emissions from conventional constructions. Existing natural-based building materials are promising for low-carbon constructions but challenging in realizing high mechanical strength for practical applications. Here, inspired by colonial sandcastles, we report the large-scale fabrication of natural-based low-carbon building materials (nLCBMs/±) by a bio-inspired adhesive strategy under low temperature and atmospheric pressure. The as-prepared nLCBMs/± show outstanding compressive strength up to the construction criteria of cement-based materials, hydration-enabled recyclability, and an anti-weathering property. Furthermore, the bio-inspired adhesive strategy is versatile to various grains, such as desert sands, sea sands, concrete slag, coal cinders, and mineral residues. Our finding provides a promising route in accelerating the next-generation construction industry with limited energy consumption and carbon emissions.