carpenter ant hole in my tree

I have a guava tree on which I been noticing dead branches. I finally went to investigate and noticed a huge hole when a branch must have broken off. The were a lot of dead tissue in the hole and carpenter ants. I cleaned out the area with drill, sprayed the ants as they fled and proceded to filling the area with Durhams putty after spraying all the surfaces with tar paint. This morning as I am applying Tanglefoot I noticed that the ants are also at the base. They seem to have eaten away a good portion of the tree from below. I cleaned and sprayed the area. My issue. I want to reach from beneath and apply a good measure of roofing cement to the affected area and thus keep ants from entering their old home. Will roofing cement do the trick. It cant hurt at this point. That and keep area around d the tree clean. Thnk you