Dtu 20 - 12 - roof and watertightness masonry . masonry structural work for roofs intended to receive a waterproof blanket - part 1 : technical specifications Dtu 20 - 12 .屋顶和不透水的砖石工程.屋顶用防水覆盖层砖石工程结构.第1部分:技术规范
All internal wall surfaces of kitchen , bathroom and latrine accommodation should be imperviously tiled or surfaced with smooth impervious material to a height of not less than 1 . 22m ( 4ft . ) 厨房、浴室及厕所的内墙应铺砌不透水的磁砖，或平滑而不透水的材料，铺砌高度不少于1 . 22米( 4尺)
The resulting landscape is dominated by impervious surfaces ? parking lots , roads , sidewalks , rooftops and construction sites compacted by heavy equipment ? that do not let water soak through 最后形成的景观就是由不透水的地面所主宰停车场、道路、人行道、屋顶，以及由重型机械压实的建筑工地，水都无法渗入这些地方。
The spring inpours from the south and pours to the north . regular water line is kept all the year round . ? ? record of daming lake was kept early in " shuijingzhu " by the famous geographer li daoyuan of the beiwei dynasty 泉水由南岸流入，水满时从宋代修建于北岸的北水门流出，湖底由不透水的火成岩构成，因而湖水“恒雨不涨，久旱不涸” ，常年保持较固定的水位。
The jinan spring catchment is a complicated karst water system , the following major work had been done in order to discuss the proplem of spring protection and water supply . 1 . having conduced exploration , experiment and comprehensive research , the southern boundary of the jinan spring catchment is determined to be the surface water divide ( changecheng mountain ) , the source of yufu river and baedasha river ; the northern one is the carbonniferous and permian strata , together with the igneous rock mass in the north of jinan , and the eastern and the western ones are dongwu and mashan faults respectively , which are weakly permeable boundaries . the total area of the spring catchment is 1486 km2 济南泉域为一复杂的岩溶水系统，为了探讨保泉供水问题，主要做了以下工作： (一)经过勘查、试验和综合研究确定济南泉域边界是：南边界为玉符河、北大沙河源头的地表水分水岭(即长城岭) ；北边界为济南北部的石炭、二迭系煤系地层和岩浆岩体；东、西两侧分别以弱透水的济南东部的东坞断裂和西部的马山断裂为边界。
