beside cement with sahara you should really put waterproofing material. para sigurado kasi pag nag-crack yang cement tutulo yan. even ceramic tiles is no guarantee that it will not leak, expecially if the cement develops cracks (due to expansion/contraction as the temperature changes during the day, or earthquake). dapat para sigurado cement with sahara, then waterproofing sheet, then cement with sahara again (manipis na lang mga 1 inch). parang asphalt sheets yung waterproofing material.

pero kung tipid, cement with sahara, then makapal na elastomeric paint o kaya yung rubberized paint na gamit sa car park ng malls.