Bottom Tommy Drains

When installing plastic fittings into cement or brickwork, you can achieve a good bond between the plastic and the mortar mix by heavily covering the surfaces that will be in contact with the mortar in solvent glue. While the glue is still wet smother it in sand. The glue will partially dissolve the surface, permanently biding the sand into the surface of the plastic. Once dry (allow at least 24 hours), this will provide an ideal surface for the mortar to bind to.

Example shown below.