1 layer of 0.25mm thick polythene sheeting laid with double...
a1 layer of 0.25mm thick polythene sheeting laid with double welded lolds on lean concrete to receive concrete bed (measured nett - no allowance made lorlaps) to floor slab 1层数0.25mm厚实聚乙稀覆盖放置与双重被焊接的lolds在精瘦的混凝土接受具体床 (被测量的nett -没有做难倒) 平板的lorlaps的...