Abstract:The effects of redispersible emulsion powder, cellulose ether and starch ether on working performance, sag resistance and mechanical properties of building sealing mortar were studied by using the method designed by the authors. The results show that: after adding the emulsion powder to the sealing mortar, the extrusion time is remarkably reduced, but the sag resistance is reduced. After adding the cellulose ether to the sealing mortar, the sag resistance of the sealing mortar is significantly improved, but the extrusion time increases and the strength decreases obviously. The starch ether, emulsion powder and cellulose ether used in conjunction in the sealing mortar can lead to better extrusion performance and sag resistance of the sealing mortar, but the strength decreases.