ระบบระบายน้ำฝน - AN OVERVIEW

eight. Correct ventilation must also be taken into consideration when building a concrete drain on a flat roof. Suitable airflow is important to avoid moisture buildup, which can cause harm and deterioration with the roof.PVC: Plumbers are using polyvinyl chloride (PVC) as a less expensive alternative to Forged iron for over a century now. It is a