FASCINATION ABOUT ท่อน้ำฝน

Use wood stakes and Mason’s line or chalk line to create a sq. or rectangular form around the marked location. Be certain the formwork is amount and safe. When developing the formwork, make allowance with the slope in direction of the middle from the drain.อ้างอิง-ภาพ : สำนักงานทรัพยากรน้�