ท่อน้ำฝน THINGS TO KNOW BEFORE YOU BUY

8. Correct ventilation should also be taken into account when building a concrete drain with a flat roof. Suitable airflow is essential to forestall dampness buildup, which can cause injury and deterioration on the roof.PVC: Plumbers have already been working with polyvinyl chloride (PVC) as a less expensive substitute to cast iron for over a cent