In nature, social insects, such as ants, bees, and termites, build large scale functional structures while tolerant to severe environmental disturbances and local failures. We propose a system composed of swarms of mobile soft robots able to collectively construct three-dimensional structures according to human-specified goals. Such goals may range from shape-templates to structures that shield from light, heat, or water. Soft robots may be able to navigate through unstructured terrain, be resistant to high impacts and a wide range of chemicals, and be cheaply manufactured. In alignment with their natural counterparts, we aim to create a system which is capable of long-term autonomous operation and is robust to failures both on the collective and individual level.