平瓦、土瓦屋面暴露在大气之中,最易积存灰尘。时间长久,积灰堵塞了瓦的流水槽如图1,雨水不能畅流,往往溢入屋面以下,造成漏雨渗水。尤其在烟灰较大的地区,如靠近铁路沿线,钢铁厂、水泥厂、发电厂等附近的房屋,积灰更多,如不及时清 Tiles and earthen tile roofs are exposed to the atmosphere and dust is most likely to accumulate. For a long time, the dust sink blocked the tile sink. Figure 1 shows that the rain can not flow smoothly and often spills under the roof, causing leakage of water. Especially in areas with large soot, such as near railways, houses near steel plants, cement plants, power plants, etc., have more ash, if not timely