Abstract: A modular building system for configuring a building structure includes foundation units, a plurality of wall panels, a plurality of wall joints and a roof unit. The foundation units are retained by an anchoring member or ballast contained in the units. The foundation units and wall panels are detachably attached as the engaging members and the complementary engaging members engage to each other and create a space with a top opening. Adjacent wall panels are attached by a plurality of wall joints. The roof unit comprises roof panels and joints engage with one another and with wall panels for covering the top opening of the building structure.

Abstract: Disclosed is a modular building system for configuring a building structure. The modular building system includes a foundation member, a plurality of wall members, a plurality of wall-retaining members and a roofing member. The foundation member has a plurality of engaging members that engages with a plurality of complementary engaging members of wall members. The foundation member and the wall members are detachably attached as the engaging members and the complementary engaging members engage to each other and create a space with a top opening. The adjacent wall members are attached by a plurality of the wall-retaining members. Further, the wall member includes a plurality of engagement members that engages with a plurality of complementary engagement members provided on the roofing member to detachably attach the plurality of engagement members on top portion of the plurality of wall members for covering the top opening, thereby configuring the building structure.