ระบบระบายน้ำฝน - AN OVERVIEW

8. Right air flow also needs to be taken into account when creating a concrete drain on the flat roof. Adequate airflow is essential to avoid dampness buildup, which can lead to destruction and deterioration with the roof.PVC: Plumbers are already employing polyvinyl chloride (PVC) as a less expensive substitute to Forged iron for more than a cent