A building formwork module is described for use in a modular formwork system. The building formwork module comprises a body portion defining at least one elongate channel that extends through the building formwork module, the body portion having at least two sides. A first side is provided with a first distancing means that is arranged such when the first side is disposed in abutting relationship with a side of an adjacent building formwork module an elongate gap is defined between the first side and the side of the adjacent module. A settable material can be directed into the at least one elongate channel and the elongate gap between two adjacent modules.