I'm in the process of purchasing a home in Michigan where the temp is already hovering around the low 30s to mid teens most of the time. To approve the loan, the bank wants us to repair some cracks in the cinder block wall on the exterior of the basement. It looks like mortar came out and someone attempted to fill with caulk but the crack enlarged and the caulk is peeling away. I picked up a high-end mortar fix comound that was recommended by a local home repair shop but the instructions say the temp needs to be in the 40s or higher. Is there a compound that will work in colder temps or do I need to set up a heater near the area of the repairs to make this work?