can this fill a 3/4 inch gap

Thank you for posting your inquiry on DAP Flexible Floor Patch and Leveler. As indicated on the product package label and supporting product literature: "Apply up to ¼ inch and let dry approximately 6 hours to a hard consistency. For thickness greater than ¼ inch, apply in multiple coats allowing each coat to dry completely between application. Feather edge all applications to ensure a smooth surface. Maximum application depth is ¾ of an inch." Should you have any additional questions or require further assistance, please contact DAP’s Technical Customer Service Department at 888-327-8477.